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#include <iostream>
#include <string>
#include <cmath>
using namespace std;

void startProgram();
void firstSelect(char);
void geometrySelect(char);

void triangleSelect(char);
void rightTriangleSelect(char);
void equilateralTriangleSelect(char);
void differentSideTriangleSelect(char);
void circleOnATriangleSelect(char);
void circleInATriangleSelect(char);

void polygonsSelect(char);
void parallelogramSelect(char);
void trapezoidSelect(char);
void rhombusSelect(char);
void rectangleSelect(char);
void squareSelect(char);

void arithmeticSelect(char);

void measurementUnitsConverterSelect(char);
void weightMeasurementUnitsSelect(char);
void lenghtMeasurementUnitsSelect(char);
void volumeMeasurementUnitsSelect(char);
void timeMeasurementUnitsSelect(char);

void equationSelect(char);

void mathematicalOperationsSelect(char);

class Triangle{
	public :
		int firstPage;
		int secondPage;
		int thirdPage;
		double firstPage1;
		double secondPage1;
		double thirdPage1;
		double stem;
		double height;
		double radius;
		double perimeter;
		
		void triangle_perimeter(){
			int first_page, second_page, third_page;
			cout << "\nEnter triangle first page - ";
			cin >> first_page;
			cout << endl;
			cout << "Enter triangle second page - ";
			cin >> second_page;
			cout << endl;
			cout << "Enter triangle third page - ";
			cin >> third_page;
			cout << endl;
			
			this->firstPage = first_page;
			this->secondPage = second_page;
			this->thirdPage = third_page;
		}
		
		void triangle_area(){
			double stem, height;
			cout << "\nEnter triangle height - ";
			cin >> stem;
			cout << endl;
			cout << "Enter triangle stem - ";
			cin >> height;
			cout << endl;

			this->height = height;
			this->stem = stem;
		}
		
		int getTrianglePerimeter(){
			return (firstPage + secondPage + thirdPage);
		}
		
		double getTriangleArea(){
			return (stem*height)/2;
		}
};

class RightTriangle: public Triangle{
	public:
		void right_triangle_area(){
			double right_first_page, right_second_page;
			cout << "\nEnter first straight page - ";
			cin >> right_first_page;
			cout << endl;
			cout << "Enter second straight page - ";
			cin >> right_second_page;
			cout << endl;
			
			this->height = right_first_page;
			this->stem = right_second_page;
		}
};

class EquilateralTriangle: public Triangle{
	public :
		void equilateral_area(){
			double triangle_page;
			cout << "\nEnter triangle page - ";
			cin >> triangle_page;
			cout << endl;
			
			this->firstPage1=triangle_page;
		}
		
		double getEquilateralArea(){
			return (pow(firstPage1, 2)*(sqrt(3)/4));
		}
};


class CircleOnATriangle: public Triangle{
	public :
		void circle_on_a_triangle_area(){
			double first_page, second_page, third_page, radius1;
			cout << "\nEnter first page of triangle - ";
			cin >> first_page;
			cout << endl;
			cout << "Enter second page of triangle - ";
			cin >> second_page;
			cout << endl;
			cout << "Enter third page of triangle - ";
			cin >> third_page;
			cout << endl;
			cout << "Enter radius of the circle - ";
			cin >> radius1;
			cout << endl;
			
			this->firstPage1 = first_page;
			this->secondPage1 = second_page;
			this->thirdPage1 = third_page;
			this->radius = radius1;
		}
		
		double getCircleOnATriangleArea(){
			return ((firstPage1 * secondPage1 * thirdPage1) / (4 * radius));
		}
};

class CircleInATriangle: public Triangle{
	public :
		void circle_in_a_triangle_area(){
			double first_page, second_page, third_page, radius1;
			cout << "\nEnter first page of triangle - ";
			cin >> first_page;
			cout << endl;
			cout << "Enter second page of triangle - ";
			cin >> second_page;
			cout << endl;
			cout << "Enter third page of triangle - ";
			cin >> third_page;
			cout << endl;
			cout << "Enter radius of the circle - ";
			cin >> radius1;
			cout << endl;
			
			this->firstPage1 = first_page;
			this->secondPage1 = second_page;
			this->thirdPage1 = third_page;
			this->radius = radius1;
		}
		
		void circle1_in_a_triangle_area1(){
			double perimeter1, radius1;
			cout << "\nEnter perimeter of the triangle - ";
			cin >> perimeter1;
			cout << endl;
			cout << "\nEnter radius of the circle - ";
			cin >> radius1;
			cout << endl;
			
			this->perimeter = perimeter1;
			this->radius = radius1;
		}
		
		double getCircleInATriangleArea(){
			return (radius * ( (firstPage1 + secondPage1 + thirdPage1) / 2));
		}
		
		double get1CircleInATriangleArea1(){
			return (radius * (perimeter/2));
		}
};

class Polygons{
	public :
		int firstPage;
		int secondPage;
		int thirdPage;
		int fourthPage;
		
		double firstPage1;
		double secondPage2;
		double height;
		
		int getOnePagePerimeter(){
			return (4 * firstPage);
		}
		
		int getTwoPagePerimeter(){
			return (2 * (firstPage + secondPage));
		}
		
		int getFourPagePerimeter(){
			return (firstPage + secondPage + thirdPage + fourthPage);
		}
		
		int getPolygonsArea(){
			return (firstPage * secondPage);
		}
};

class Parallelogram: public Polygons{
	public :
		void parallelogram_perimeter(){
			int first_page, second_page;
			cout << "Enter parallelogram first page - ";
			cin >> first_page;
			cout << endl;
			cout << "Enter parallelogram second page - ";
			cin >> second_page;
			cout << endl;
			
			this->firstPage = first_page;
			this->secondPage = second_page;
		}
		
		void parallelogram_area(){
			int stem, height;
			cout << "Enter parallelogram stem page - ";
			cin >> stem;
			cout << endl;
			cout << "Enter parallelogram heigt - ";
			cin >> height;
			cout << endl;
			
			this->firstPage = stem;
			this->secondPage = height;
		}
		
};

class Rectangle: public Polygons{
	public :
		void rectangle_perimeter(){
			int first_page, second_page;
			cout << "Enter rectangle first page - ";
			cin >> first_page;
			cout << endl;
			cout << "Enter rectangle second page - ";
			cin >> second_page;
			cout << endl;
			
			this->firstPage = first_page;
			this->secondPage = second_page;
		}
		
		void rectangle_area(){
			int first_page, second_page;
			cout << "Enter rectangle first page - ";
			cin >> first_page;
			cout << endl;
			cout << "Enter rectangle second page - ";
			cin >> second_page;
			cout << endl;
			
			this->firstPage = first_page;
			this->secondPage = second_page;
		}
};

class Square: public Polygons{
	public :
		void square_perimeter(){
			int page;
			cout << "Enter square page - ";
			cin >> page;
			cout << endl;

			this->firstPage = page;
		}
		
		void square_area(){
			int page;
			cout << "Enter square page - ";
			cin >> page;
			cout << endl;

			
			this->firstPage = page;
			this->secondPage = page;
		}
};

class Rhombus: public Polygons{
	public :
		void rhombus_perimeter(){
			int page;
			cout << "Enter rhombus page - ";
			cin >> page;
			cout << endl;

			this->firstPage = page;
		}
		
		void rhombus_area(){
			int first_page, second_page;
			cout << "Enter rhombus page - ";
			cin >> first_page;
			cout << endl;
			cout << "Enter rhombus height - ";
			cin >> second_page;
			cout << endl;
			
			this->firstPage = first_page;
			this->secondPage = second_page;
		}
		
		void rhombus_area1(){
			double diagonal1, diagonal2;
			cout << "Enter rhombus first diagonal - ";
			cin >> diagonal1;
			cout << endl;
			cout << "Enter rhombus second diagonal - ";
			cin >> diagonal2;
			cout << endl;
			
			this->firstPage = diagonal1;
			this->secondPage = diagonal2;
		}
		
		double getRhombusArea(){
			return ((firstPage1 * secondPage2) / 2);
		}
};

class Trapezoid: public Polygons{
	public :
		void trapezoid_perimeter(){
			int first_page, second_page, third_page, fourth_page;
			cout << "Enter trapezoid first page - ";
			cin >> first_page;
			cout << endl;
			cout << "Enter trapezoid second page - ";
			cin >> second_page;
			cout << endl;
			cout << "Enter trapezoid third page - ";
			cin >> third_page;
			cout << endl;
			cout << "Enter trapezoid fourth page - ";
			cin >> fourth_page;
			cout << endl;
			
			this->firstPage = first_page;
			this->secondPage = second_page;
			this->thirdPage = third_page;
			this->fourthPage = fourth_page;
		}
		
		void trapezoid_area(){
			double first_stem, second_stem, height1;
			cout << "Enter trapezoid little stem - ";
			cin >> first_stem;
			cout << endl;
			cout << "Enter trapezoid big stem - ";
			cin >> second_stem;
			cout << endl;
			cout << "Enter trapezoid height - ";
			cin >> height1;
			cout << endl;
			
			this->firstPage1 = first_stem;
			this->secondPage2 = second_stem;
			this->height = height1;
		}
		
		double getTrapezoidArea(){
			return (((firstPage1 + secondPage2) * height) / 2);
		}
};

class Weight{
	public :
		double size;
		void tons_size(){
			double tons;
			cout << "Enter tons - ";
			cin >> tons;
			cout << endl;
			
			this->size = tons;
		}
		
		void kilogram_size(){
			double kilogram;
			cout << "Enter kilogram - ";
			cin >> kilogram;
			cout << endl;
			
			this->size = kilogram;
		}
		
		void gram_size(){
			double gram;
			cout << "Enter gram - ";
			cin >> gram;
			cout << endl;
			
			this->size = gram;
		}
		
		double get_tons_to_kilogram(){
			return size*1000;
		}
		
		double get_kilogram_to_tons(){
			return size/1000;
		}
		
		double get_tons_to_gram(){
			return size*1000000;
		}
		
		double get_gram_to_tons(){
			return size/1000000;
		}
		
		double get_kilogram_to_gram(){
			return size*1000;
		}
		
		double get_gram_to_kilogram(){
			return size/1000;
		}
};

class Length{
	public :
		double size;
		void kilometer_size(){
			double kilometer;
			cout << "Enter kilometer - ";
			cin >> kilometer;
			cout << endl;
			
			this->size = kilometer;
		}
		
		void meter_size(){
			double meter;
			cout << "Enter meter - ";
			cin >> meter;
			cout << endl;
			
			this->size = meter;
		}
		
		void centimeter_size(){
			double centimeter;
			cout << "Enter centimeter - ";
			cin >> centimeter;
			cout << endl;
			
			this->size = centimeter;
		}
		
		void millimeter_size(){
			double millimeter;
			cout << "Enter millimeter - ";
			cin >> millimeter;
			cout << endl;
			
			this->size = millimeter;
		}
		
		double get_kilometer_to_meter(){
			return size*1000;
		}
		
		double get_meter_to_kilometer(){
			return size/1000;
		}
		
		double get_kilometer_to_centimeter(){
			return size*100000;
		}
		
		double get_centimeter_to_kilometer(){
			return size/100000;
		}
		
		double get_kilometer_to_millimeter(){
			return size*1000000;
		}
		
		double get_millimeter_to_kilometer(){
			return size/1000000;
		}
		
		double get_meter_to_centimeter(){
			return size*100;
		}
		
		double get_centimeter_to_meter(){
			return size/100;
		}
		
		double get_meter_to_millimeter(){
			return size*1000;
		}
		
		double get_millimeter_to_meter(){
			return size/1000;
		}
		
		double get_centimeter_to_millimeter(){
			return size*10;
		}
		
		double get_millimeter_to_centimeter(){
			return size/10;
		}
};

class Volume{
	public :
		double size;
		void liter_size(){
			double liter;
			cout << "Enter liter - ";
			cin >> liter;
			cout << endl;
			
			this->size = liter;
		}
		
		void milliliter_size(){
			double milliliter;
			cout << "Enter milliliter - ";
			cin >> milliliter;
			cout << endl;
			
			this->size = milliliter;
		}
		
		double get_liter_to_milliliter(){
			return size*1000;
		}
		
		double get_milliliter_to_liter(){
			return size/1000;
		}
};

class Time{
	public :
		double size;
		void hour_size(){
			double hour;
			cout << "Enter hour - ";
			cin >> hour;
			cout << endl;
			
			this->size = hour;
		}
		
		void minute_size(){
			double minute;
			cout << "Enter minute - ";
			cin >> minute;
			cout << endl;
			
			this->size = minute;
		}
		
		void second_size(){
			double second;
			cout << "Enter second - ";
			cin >> second;
			cout << endl;
			
			this->size = second;
		}
		
		double get_hour_to_minute(){
			return size*60;
		}
		
		double get_minute_to_hour(){
			return size/60;
		}
		
		double get_hour_to_second(){
			return size*3600;
		}
		
		double get_second_to_hour(){
			return size/3600;
		}
		
		double get_minute_to_second(){
			return size*60;
		}
		
		double get_second_to_minute(){
			return size/60;
		}
};

class LinearEquation{
	public :
		double a;
		double b;
		double c;
		void first_linear_equation(){
			double a1, b1, c1;
			cout << "\nax + b = c" << endl;
			cout << "Enter a - ";
			cin >> a1;
			cout << endl;
			cout << "Enter b - ";
			cin >> b1;
			cout << endl;
			cout << "Enter c - ";
			cin >> c1;
			cout << endl;
			
			this->a = a1;
			this->b = b1;
			this->c = c1;
		}
		
		void second_linear_equation(){
			double a2, b2;
			cout << "\nax = b" << endl;
			cout << "Enter a - " << endl;
			cin >> a2;
			cout << endl;
			cout << "Enter b - " << endl;
			cin >> b2;
			cout << endl;
			
			this->a = a2;
			this->b = b2;
		}
		
		double get_first_equation(){
			return ((c - b) / a);
		}
		
		double get_second_equation(){
			return (b / a);
		}
};

class QuadraticEquation{
	public :
		double a;
		double b;
		double c;
		void first_quadratic_equation(){
			double a1, b1, c1;
			cout << "\nax^2 + bx + c = 0, a != 0" << endl;
			cout << "Enter a - ";
			cin >> a1;
			cout << endl;
			cout << "Enter b - ";
			cin >> b1;
			cout << endl;
			cout << "Enter c - ";
			cin >> c1;
			cout << endl;
			
			if(a1 == 0){
				cout << "You enter the number incorrectly, a != 0, So answer may be incorrectly" << endl;
			}
			
			this->a = a1;
			this->b = b1;
			this->c = c1;
		}
		
		void second_quadratic_equation(){
			double a2, b2;
			cout << "\nax^2 + bx = 0, a != 0" << endl;
			cout << "Enter a - ";
			cin >> a2;
			cout << endl;
			cout << "Enter b - ";
			cin >> b2;
			cout << endl;
			
			if(a2 == 0){
				cout << "You enter the number incorrectly, a != 0, So answer may be incorrectly" << endl;
			}
			
			this->a = a2;
			this->b = b2;
		}
		
		void third_quadratic_equation(){
			double a3;
			cout << "\nax^2 = 0, a != 0";
			cout << "Enter a - ";
			cin >> a3;
			cout << endl;
			
			if(a3 == 0){
				cout << "You enter the number incorrectly, a != 0, So answer may be incorrectly" << endl;
			}
		}
				
		double get_x1_first_quadratic_equation(){
			return ((-b + sqrt(pow(b,2) - ( 4 * a * c ))) / (2 * a));
		}
		
		double get_x2_first_quadratic_equation(){
			return ((-b - sqrt(pow(b,2) - ( 4 * a * c ))) / (2 * a));
		}
		
		double get_x_second_quadratic_equation(){
			return ((-b) / a);
		}
};

class MathematicalOperations{
	public:
		
		void mathematical_operation(){
			char op;
		    float num1, num2;
		
		    cout << "Enter operator: +, -, *, /  - ";
		    cin >> op;
		
		    cout << "Enter first operand: ";
		    cin >> num1;
		    cout << "Enter second operand: ";
		    cin >> num2;
		    cout << endl;
		
		    
			switch(op) {
		        case '+':
		            cout << num1 << " + " << num2 << " = " << num1 + num2 << endl;
		            break;
		
		        case '-':
		            cout << num1 << " - " << num2 << " = " << num1 - num2 << endl;
		            break;
		
		        case '*':
		            cout << num1 << " * " << num2 << " = " << num1 * num2 << endl;
		            break;
		
		        case '/':
		            cout << num1 << " / " << num2 << " = " << num1 / num2 << endl;
		            break;
		            
		        default:
		        	cout << "Error! operation is not correct";
		        	break;
		    }
		}
};

int main(){	
	
	char select;
	
	startProgram();
	
	firstSelect(select);
	
	
	
	
	
	return 0;
}

	// Program start
void startProgram(){
	cout << "Hello, I'm a smart calculator!" << endl;
	cout << "I will try to contact you in a language you understand!" << endl;
	cout << "Please when making a selection enter the character that is in quotation marks!" << endl;
	cout << "If everything understand we can start!" << endl;
}

	// Make the first choice
void firstSelect(char first_select){
	cout << "\nSelect what you want!" << endl;
	cout << "Geometry - 'G'\nArithmetic - 'A'" << endl;
	cout << "Enter the selected character - ";
	cin >> first_select;	
	switch(first_select){
		case 'G':
		case 'g':
			geometrySelect(first_select);
			break;
		case 'A':
		case 'a':
			arithmeticSelect(first_select);
			break;
		default:
			cout << "\nWrong character!" << endl;
			firstSelect(first_select);
			break;
	}
}

	// Make the geometry choice
void geometrySelect( char geometry_select){
	cout << "\nSelect what you want!" << endl;
	cout << "Triangle - 'T'\nPolygons - 'P'\nGo back - 'B'" << endl;
	cout << "Enter the selected character - ";
	cin >> geometry_select;
	switch(geometry_select){
		case 'T':
		case 't':
			triangleSelect(geometry_select);
			break;
		case 'P':
		case 'p':
			polygonsSelect(geometry_select);
			break;
		case 'B':
		case 'b':
			firstSelect(geometry_select);
			break;
		default:
			cout << "\nWrong character!" << endl;
			geometrySelect(geometry_select);
			break;
	}
}

	// Make the triangle choice
void triangleSelect(char triangle_select){
	cout << "\nSelect what you want!" << endl;
	cout << "Right triangle - 'R'\nEquilateral triangle - 'E'\nDifferent side triangle - 'D'\nCircle on a triangle - 'O'\nCircle in a triangle - 'I'\nGo back - 'B'" << endl;
	cout << "Enter the selected character - ";
	cin >> triangle_select;
	switch(triangle_select){
		case 'R':
		case 'r':
			rightTriangleSelect(triangle_select);
			break;
		case 'E':
		case 'e':
			equilateralTriangleSelect(triangle_select);
			break;
		case 'D':
		case 'd':
			differentSideTriangleSelect(triangle_select);
			break;
		case 'O':
		case 'o':
			circleOnATriangleSelect(triangle_select);
			break;
		case 'I':
		case 'i':
			circleInATriangleSelect(triangle_select);
			break;
		case 'B':
		case 'b':
			geometrySelect(triangle_select);
			break;
		default:
			cout << "\nWrong character!" << endl;
			triangleSelect(triangle_select);
			break;
	}
}

	// Make the right triangle choice
void rightTriangleSelect(char right_triangle_select){
	cout << "\nSelect what you want!" << endl;
	cout << "Perimeter - 'P'\nArea - 'A'\nGo back - 'B'" << endl;
	cout << "Enter the selected character - ";
	cin >> right_triangle_select;
	switch(right_triangle_select){
		case 'P':
		case 'p':
			RightTriangle object;
			object.triangle_perimeter();
			cout << "Triangle perimeter = " << object.getTrianglePerimeter() << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> right_triangle_select;
			switch(right_triangle_select){
				case 'O':
				case 'o':
					firstSelect(right_triangle_select);
					break;
				case 'B':
				case 'b':
					rightTriangleSelect(right_triangle_select);
					break;
				default: 
					cout << "Program is suspended" << endl;
					break;					
			}
			break;
		case 'A':
		case 'a':
			cout << "\nWe have 2 way to solve the example,\nI will tell you what we need for each and\nyou choose the one that will be useful for you." << endl;
			cout << "1. The stem of the triangle and the allowable height on it - 'F'\n2. Two straight pages - 'S'\nGo back - 'B'" << endl;
			cout << "Enter the selected character - ";
			cin >> right_triangle_select;
			switch(right_triangle_select){
				case 'F':
				case 'f':
					RightTriangle object;
					object.triangle_area();
					cout << "Triangle area = " << object.getTriangleArea() << endl;
					cout << "\nPlease tell me what you want now!" << endl;
					cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
					cout << "Enter the selected character - ";
					cin >> right_triangle_select;
					switch(right_triangle_select){
						case 'O':
						case 'o':
							firstSelect(right_triangle_select);
							break;
						case 'B':
						case 'b':
							rightTriangleSelect(right_triangle_select);
							break;
						default:
							cout << "Program is suspended" << endl;
							break;
					}
					break;
				case 'S':
				case 's':
					RightTriangle object1;
					object1.right_triangle_area();
					cout << "Triangle area = " << object1.getTriangleArea() << endl;
					cout << "\nPlease tell me what you want now!" << endl;
					cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
					cout << "Enter the selected character - ";
					cin >> right_triangle_select;
					switch(right_triangle_select){
						case 'O':
						case 'o':
							firstSelect(right_triangle_select);
							break;
						case 'B':
						case 'b':
							rightTriangleSelect(right_triangle_select);
							break;
						default:
							cout << "Program is suspended" << endl;
							break;
					}
					break;
				case 'B':
				case 'b':
					rightTriangleSelect(right_triangle_select);
					break;
				default:
					cout << "\nWrong character!" << endl;
					rightTriangleSelect(right_triangle_select);
					break;
			}
			break;
		case 'B':
		case 'b':
			triangleSelect(right_triangle_select);
			break;
		default:
			cout << "\nWrong character!" << endl;
			rightTriangleSelect(right_triangle_select);
			break;
	}
}

	// Make the equilateral triangle choice
void equilateralTriangleSelect(char equilateral_triangle_select){
	cout << "\nSelect what you want!" << endl;
	cout << "Perimeter - 'P'\nArea - 'A'\nGo back - 'B'" << endl;
	cout << "Enter the selected character - ";
	cin >> equilateral_triangle_select;
	switch(equilateral_triangle_select){
		case 'P':
		case 'p':
			EquilateralTriangle object;
			object.triangle_perimeter();
			cout << "Triangle perimeter = " << object.getTrianglePerimeter() <<endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> equilateral_triangle_select;
			switch(equilateral_triangle_select){
				case 'O':
				case 'o':
					firstSelect(equilateral_triangle_select);
					break;
				case 'B':
				case 'b':
					equilateralTriangleSelect(equilateral_triangle_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'A':
		case 'a':
			cout << "\nWe have 2 way to solve the example,\nI will tell you what we need for each and\nyou choose the one that will be useful for you." << endl;
			cout << "1. The stem of the triangle and the allowable height on it - 'F'\n2. Any one page - 'S'\nGo Back - 'B'" << endl;
			cout << "Enter the selected character - ";
			cin >> equilateral_triangle_select;
			switch(equilateral_triangle_select){
				case 'F':
				case 'f':
					EquilateralTriangle object;
					object.triangle_area();
					cout << "Triangle area = " << object.getTriangleArea() << endl;
					cout << "\nPlease tell me what you want now!" << endl;
					cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
					cout << "Enter the selected character - ";
					cin >> equilateral_triangle_select;
					switch(equilateral_triangle_select){
						case 'O':
						case 'o':
							firstSelect(equilateral_triangle_select);
							break;
						case 'B':
						case 'b':
							equilateralTriangleSelect(equilateral_triangle_select);
							break;
						default:
							cout << "Program is suspended" << endl;
							break;
					}
					break;
				case 'S':
				case 's':
					EquilateralTriangle object1;
					object1.equilateral_area();
					cout << "Triangle area = " << object1.getEquilateralArea() << endl;
					cout << "\nPlease tell me what you want now!" << endl;
					cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
					cout << "Enter the selected character - ";
					cin >> equilateral_triangle_select;
					switch(equilateral_triangle_select){
						case 'O':
						case 'o':
							firstSelect(equilateral_triangle_select);
							break;
						case 'B':
						case 'b':
							equilateralTriangleSelect(equilateral_triangle_select);
							break;
						default:
							cout << "Program is suspended" << endl;
							break;
					}
					break;
				case 'B':
				case 'b':
					equilateralTriangleSelect(equilateral_triangle_select);
					break;
				default:
					cout << "\nWrong character!" << endl;
					equilateralTriangleSelect(equilateral_triangle_select);
					break;
			}
			break;
		case 'B':
		case 'b':
			triangleSelect(equilateral_triangle_select);
			break;
		default:
			cout << "\nWrong character!" << endl;
			equilateralTriangleSelect(equilateral_triangle_select);
			break;
	}
}

	// Make the different side triangle choice
void differentSideTriangleSelect(char different_side_triangle_select){
	cout << "\nSelect what you want!" << endl;
	cout << "Perimeter - 'P'\nArea - 'A'\nGo back - 'B'" << endl;
	cout << "Enter the selected character - ";
	cin >> different_side_triangle_select;
	switch(different_side_triangle_select){
		case 'P':
		case 'p':
			Triangle object;
			object.triangle_perimeter();
			cout << "Triangle perimeter = " << object.getTrianglePerimeter() << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> different_side_triangle_select;
			switch(different_side_triangle_select){
				case 'O':
				case 'o':
					firstSelect(different_side_triangle_select);
					break;
				case 'B':
				case 'b':
					differentSideTriangleSelect(different_side_triangle_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'A':
		case 'a':
			Triangle object1;
			object1.triangle_area();
			cout << "Triangle area = " << object1.getTriangleArea() << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> different_side_triangle_select;
			switch(different_side_triangle_select){
				case 'O':
				case 'o':
					firstSelect(different_side_triangle_select);
					break;
				case 'B':
				case 'b':
					differentSideTriangleSelect(different_side_triangle_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'B':
		case 'b':
			triangleSelect(different_side_triangle_select);
			break;
		default:
			cout << "\nWrong character!" << endl;
			differentSideTriangleSelect(different_side_triangle_select);
			break;
	}
}

	// Make the circle on a triangle choice
void circleOnATriangleSelect(char circle_on_a_triangle_select){
	cout << "\nSelect what you want!" << endl;
	cout << "Perimeter - 'P'\nArea - 'A'\nGo back - 'B'" << endl;
	cout << "Enter the selected character - ";
	cin >> circle_on_a_triangle_select;
	switch(circle_on_a_triangle_select){
		case 'P':
		case 'p':
			CircleOnATriangle object;
			object.triangle_perimeter();
			cout << "Triangle perimeter = " << object.getTrianglePerimeter() << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> circle_on_a_triangle_select;
			switch(circle_on_a_triangle_select){
				case 'O':
				case 'o':
					firstSelect(circle_on_a_triangle_select);
					break;
				case 'B':
				case 'b':
					circleOnATriangleSelect(circle_on_a_triangle_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'A':
		case 'a':
			cout << "\nWe have 2 way to solve the example,\nI will tell you what we need for each and\nyou choose the one that will be useful for you." << endl;
			cout << "\n1. The stem of the triangle and the allowable height on it - 'F'\n2. All page and circle radius - 'S'\nGo Back - 'B'" << endl;
			cout << "Enter the selected character - ";
			cin >> circle_on_a_triangle_select;
			switch(circle_on_a_triangle_select){
				case 'F':
				case 'f':
					CircleOnATriangle object;
					object.triangle_area();
					cout << "Triangle area = " << object.getTriangleArea() << endl;
					cout << "\nPlease tell me what you want now!" << endl;
					cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
					cout << "Enter the selected character - ";
					cin >> circle_on_a_triangle_select;
					switch(circle_on_a_triangle_select){
						case 'O':
						case 'o':
							firstSelect(circle_on_a_triangle_select);
							break;
						case 'B':
						case 'b':
							circleOnATriangleSelect(circle_on_a_triangle_select);
							break;
						default:
							cout << "Program is suspended" << endl;
							break;
					}
					break;
				case 'S':
				case 's':			
					CircleOnATriangle object1;
					object1.circle_on_a_triangle_area();
					cout << "Triangle area = " << object1.getCircleOnATriangleArea() << endl;
					cout << "\nPlease tell me what you want now!" << endl;
					cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
					cout << "Enter the selected character - ";
					cin >> circle_on_a_triangle_select;
					switch(circle_on_a_triangle_select){
						case 'O':
						case 'o':
							firstSelect(circle_on_a_triangle_select);
							break;
						case 'B':
						case 'b':
							circleOnATriangleSelect(circle_on_a_triangle_select);
							break;
						default:
							cout << "Program is suspended" << endl;
							break;
					}
					break;
				case 'B':
				case 'b':
					circleOnATriangleSelect(circle_on_a_triangle_select);
					break;
				default:
					cout << "\nWrong character!" << endl;
					circleOnATriangleSelect(circle_on_a_triangle_select);
					break;
			}
			break;
		case 'B':
		case 'b':
			triangleSelect(circle_on_a_triangle_select);
			break;
		default:
			cout << "\nWrong character!" << endl;
			circleOnATriangleSelect(circle_on_a_triangle_select);
			break;
	}
}

	// Make the circle in a triangle choice
void circleInATriangleSelect(char circle_in_a_triangle_select){
	cout << "\nSelect what you want!" << endl;
	cout << "Perimeter - 'P'\nArea - 'A'\nGo back - 'B'" << endl;
	cout << "Enter the selected character - ";
	cin >> circle_in_a_triangle_select;
	switch(circle_in_a_triangle_select){
		case 'P':
		case 'p':
			CircleInATriangle object;
			object.triangle_perimeter();
			cout << "Triangle perimeter = " << object.getTrianglePerimeter() << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> circle_in_a_triangle_select;
			switch(circle_in_a_triangle_select){
				case 'O':
				case 'o':
					firstSelect(circle_in_a_triangle_select);
					break;
				case 'B':
				case 'b':
					circleInATriangleSelect(circle_in_a_triangle_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'A':
		case 'a':
			cout << "\nWe have 3 way to solve the example,\nI will tell you what we need for each and\nyou choose the one that will be useful for you." << endl;
			cout << "\n1. The stem of the triangle and the allowable height on it - 'F'\n2. All page and circle radius - 'S'\n3. Perimeter of triangle and radius of circle - 'T'\nGo Back - 'B'" << endl;
			cout << "Enter the selected character - ";
			cin >> circle_in_a_triangle_select;
			switch(circle_in_a_triangle_select){
				case 'F':
				case 'f':
					CircleInATriangle object;
					object.triangle_area();
					cout << "Triangle area = " << object.getTriangleArea() <<endl;
					cout << "\nPlease tell me what you want now!" << endl;
					cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
					cout << "Enter the selected character - ";
					cin >> circle_in_a_triangle_select;
					switch(circle_in_a_triangle_select){
						case 'O':
						case 'o':
							firstSelect(circle_in_a_triangle_select);
							break;
						case 'B':
						case 'b':
							circleInATriangleSelect(circle_in_a_triangle_select);
							break;
						default:
							cout << "Program is suspended" << endl;
							break;
					}
					break;
				case 'S':
				case 's':
					CircleInATriangle object1;
					object1.circle_in_a_triangle_area();
					cout << "Triangle area = " << object1.getCircleInATriangleArea() << endl;
					cout << "\nPlease tell me what you want now!" << endl;
					cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
					cout << "Enter the selected character - ";
					cin >> circle_in_a_triangle_select;
					switch(circle_in_a_triangle_select){
						case 'O':
						case 'o':
							firstSelect(circle_in_a_triangle_select);
							break;
						case 'B':
						case 'b':
							circleInATriangleSelect(circle_in_a_triangle_select);
							break;
						default:
							cout << "Program is suspended" << endl;
							break;
					}
					break;	
				case 'T':
				case 't':		
					CircleInATriangle object2;
					object2.circle1_in_a_triangle_area1();
					cout << "Triangle area = " << object2.get1CircleInATriangleArea1() << endl;
					cout << "\nPlease tell me what you want now!" << endl;
					cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
					cout << "Enter the selected character - ";
					cin >> circle_in_a_triangle_select;
					switch(circle_in_a_triangle_select){
						case 'O':
						case 'o':
							firstSelect(circle_in_a_triangle_select);
							break;
						case 'B':
						case 'b':
							circleInATriangleSelect(circle_in_a_triangle_select);
							break;
						default:
							cout << "Program is suspended" << endl;
							break;
					}
					break;
				case 'B':
				case 'b':
					circleInATriangleSelect(circle_in_a_triangle_select);
					break;
				default:
					cout << "\nWrong character!" << endl;
					circleInATriangleSelect(circle_in_a_triangle_select);
					break;
			}
			break;
		case 'B':
		case 'b':
			triangleSelect(circle_in_a_triangle_select);
			break;
		default:
			cout << "\nWrong character!" << endl;
			circleInATriangleSelect(circle_in_a_triangle_select);
			break;
	}
}

	// Make the polygons choice
void polygonsSelect(char polygons_select){
	cout << "\nSelect what you want!" << endl;
	cout << "Parallelogram - 'P'\nTrapezoid - 'T'\nRhombus - 'R'\nRectangle - 'E'\nSquare - 'S'\nGo back - 'B'" << endl;
	cout << "Enter the selected character - ";
	cin >> polygons_select;
	switch(polygons_select){
		case 'P':
		case 'p':
			parallelogramSelect(polygons_select);
			break;
		case 'T':
		case 't':
			trapezoidSelect(polygons_select);
			break;
		case 'R':
		case 'r':
			rhombusSelect(polygons_select);
			break;
		case 'E':
		case 'e':
			rectangleSelect(polygons_select);
			break;
		case 'S':
		case 's':
			squareSelect(polygons_select);
			break;
		case 'B':
		case 'b':
			geometrySelect(polygons_select);
			break;
		default:
			cout << "\nWrong character!" << endl;
			polygonsSelect(polygons_select);
			break;
	}
}

	// Make the parallelogram choice
void parallelogramSelect(char parallelogram_select){
	cout << "\nSelect what you want!" << endl;
	cout << "Perimeter - 'P'\nArea - 'A'\nGo back - 'B'" << endl;
	cout << "Enter the selected character - ";
	cin >> parallelogram_select;
	switch(parallelogram_select){
		case 'P':
		case 'p':
			Parallelogram object;
			object.parallelogram_perimeter();
			cout << "Parallelogram perimeter = " << object.getTwoPagePerimeter() << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> parallelogram_select;
			switch(parallelogram_select){
				case 'O':
				case 'o':
					firstSelect(parallelogram_select);
					break;
				case 'B':
				case 'b':
					parallelogramSelect(parallelogram_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'A':
		case 'a':
			Parallelogram object1;
			object1.parallelogram_area();
			cout << "Parallelogram area = " << object1.getPolygonsArea() << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> parallelogram_select;
			switch(parallelogram_select){
				case 'O':
				case 'o':
					firstSelect(parallelogram_select);
				case 'B':
				case 'b':
					parallelogramSelect(parallelogram_select);
				default:
					cout << "Program is suspended" << endl;
			}
			break;
		case 'B':
		case 'b':
			polygonsSelect(parallelogram_select);
			break;
		default:
			cout << "\nWrong character!" << endl;
			parallelogramSelect(parallelogram_select);
			break;
	}
}

	// Make the trapezoid choice
void trapezoidSelect(char trapezoid_select){
	cout << "\nSelect what you want!" << endl;
	cout << "Perimeter - 'P'\nArea - 'A'\nGo back - 'B'" << endl;
	cout << "Enter the selected character - ";
	cin >> trapezoid_select;
	switch(trapezoid_select){
		case 'P':
		case 'p':
			Trapezoid object;
			object.trapezoid_perimeter();
			cout << "Trapezoid perimeter = " << object.getFourPagePerimeter() << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> trapezoid_select;
			switch(trapezoid_select){
				case 'O':
				case 'o':
					firstSelect(trapezoid_select);
					break;
				case 'B':
				case 'b':
					trapezoidSelect(trapezoid_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'A':
		case 'a':
			Trapezoid object1;
			object1.trapezoid_area();
			cout << "Trapezoid area = " << object1.getTrapezoidArea() << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> trapezoid_select;
			switch(trapezoid_select){
				case 'O':
				case 'o':
					firstSelect(trapezoid_select);
					break;
				case 'B':
				case 'b':
					trapezoidSelect(trapezoid_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'B':
		case 'b':
			polygonsSelect(trapezoid_select);
			break;
		default:
			cout << "\nWrong character!" << endl;
			trapezoidSelect(trapezoid_select);
			break;
	}
}

	// Make the rhombus choice
void rhombusSelect(char rhombus_select){
	cout << "\nSelect what you want!" << endl;
	cout << "Perimeter - 'P'\nArea - 'A'\nGo back - 'B'" << endl;
	cout << "Enter the selected character - ";
	cin >> rhombus_select;
	switch(rhombus_select){
		case 'P':
		case 'p':
			Rhombus object;
			object.rhombus_perimeter();
			cout << "Rhombus perimeter = " << object.getOnePagePerimeter() << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> rhombus_select;
			switch(rhombus_select){
				case 'O':
				case 'o':
					firstSelect(rhombus_select);
					break;
				case 'B':
				case 'b':
					rhombusSelect(rhombus_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'A':
		case 'a':
			cout << "\nWe have 2 way to solve the example,\nI will tell you what we need for each and\nyou choose the one that will be useful for you." << endl;
			cout << "1. Rhombus page - 'F'\nRhombus perimeter - 'S'\ngo back - 'B'" << endl;
			cout << "Enter the selected character - ";
			cin >> rhombus_select;
			switch(rhombus_select){
				case 'F':
				case 'f':
					Rhombus object;
					object.rhombus_area();
					cout << "Rhombus area = " << object.getPolygonsArea() << endl;
					cout << "\nPlease tell me what you want now!" << endl;
					cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
					cout << "Enter the selected character - ";
					cin >> rhombus_select;
					switch(rhombus_select){
					case 'O':
					case 'o':
						firstSelect(rhombus_select);
						break;
					case 'B':
					case 'b':
						rhombusSelect(rhombus_select);
						break;
					default:
						cout << "Program is suspended" << endl;
						break;
					}
				case 'S':
				case 's':
					Rhombus object1;
					object1.rhombus_area1();
					cout << "Rhombus area = " << object1.getRhombusArea() << endl;
					cout << "\nPlease tell me what you want now!" << endl;
					cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
					cout << "Enter the selected character - ";
					cin >> rhombus_select;
					switch(rhombus_select){
					case 'O':
					case 'o':
						firstSelect(rhombus_select);
						break;
					case 'B':
					case 'b':
						rhombusSelect(rhombus_select);
						break;
					default:
						cout << "Program is suspended" << endl;
						break;
					}
					break;
				case 'B':
				case 'b':
					rhombusSelect(rhombus_select);
					break;
				default:
					cout << "\nWrong character!" << endl;
					rhombusSelect(rhombus_select);
			}
			break;
		case 'B':
		case 'b':
			polygonsSelect(rhombus_select);
			break;
		default:
			cout << "\nWrong character!" << endl;
			rhombusSelect(rhombus_select);
			break;
	}
}

	// Make the rectangle choice
void rectangleSelect(char rectangle_select){
	cout << "\nSelect what you want!" << endl;
	cout << "Perimeter - 'P'\nArea - 'A'\nGo back - 'B'" << endl;
	cout << "Enter the selected character - ";
	cin >> rectangle_select;
	switch(rectangle_select){
		case 'P':
		case 'p':
			Rectangle object;
			object.rectangle_perimeter();
			cout << "Rectangle perimeter = " << object.getTwoPagePerimeter() << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> rectangle_select;
			switch(rectangle_select){
				case 'O':
				case 'o':
					firstSelect(rectangle_select);
					break;
				case 'B':
				case 'b':
					rectangleSelect(rectangle_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'A':
		case 'a':
			Rectangle object1;
			object1.rectangle_area();
			cout << "Rectangle area = " << object1.getPolygonsArea() << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> rectangle_select;
			switch(rectangle_select){
				case 'O':
				case 'o':
					firstSelect(rectangle_select);
					break;
				case 'B':
				case 'b':
					rectangleSelect(rectangle_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'B':
		case 'b':
			polygonsSelect(rectangle_select);
			break;
		default:
			cout << "\nWrong character!" << endl;
			rectangleSelect(rectangle_select);
			break;
	}
}

	// Make the square choice
void squareSelect(char square_select){
	cout << "\nSelect what you want!" << endl;
	cout << "Perimeter - 'P'\nArea - 'A'\nGo back - 'B'" << endl;
	cout << "Enter the selected character - ";
	cin >> square_select;
	switch(square_select){
		case 'P':
		case 'p':
			Square object;
			object.square_perimeter();
			cout << "Square perimeter = " << object.getOnePagePerimeter() << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> square_select;
			switch(square_select){
				case 'O':
				case 'o':
					firstSelect(square_select);
					break;
				case 'B':
				case 'b':
					squareSelect(square_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'A':
		case 'a':
			Square object1;
			object1.square_area();
			cout << "Square area = " << object1.getPolygonsArea() << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> square_select;
			switch(square_select){
				case 'O':
				case 'o':
					firstSelect(square_select);
					break;
				case 'B':
				case 'b':
					squareSelect(square_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'B':
		case 'b':
			polygonsSelect(square_select);
			break;
		default:
			cout << "\nWrong character!" << endl;
			squareSelect(square_select);
			break;
	}
}

	//make the arithmetic choice
void arithmeticSelect(char arithmetic_select){
	cout << "\nSelect what you want!" << endl;
	cout << "Mathematical operations - 'M'\nMeasurement unit converter - 'U'\nEquation - 'E'\nGo back - 'B'" << endl;
	cout << "Enter the selected character - ";
	cin >> arithmetic_select;
	switch(arithmetic_select){
		case 'M':
		case 'm':
			MathematicalOperations object;
			object.mathematical_operation();
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> arithmetic_select;
			switch(arithmetic_select){
				case 'O':
				case 'o':
					firstSelect(arithmetic_select);
					break;
				case 'B':
				case 'b':
					arithmeticSelect(arithmetic_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'U':
		case 'u':
			measurementUnitsConverterSelect(arithmetic_select);
			break;
		case 'E':
		case 'e':
			equationSelect(arithmetic_select);
			break;
		case 'B':
		case 'b':
			firstSelect(arithmetic_select);
			break;
		default:
			cout << "\nWrong character!" << endl;
			arithmeticSelect(arithmetic_select);
			break;
	}
}

	// Make the measurement unit converter choice
void measurementUnitsConverterSelect(char measurement_unit_converter_select){
	cout << "\nSelect what you want!" << endl;
	cout << "Weight measurement units - 'W'\nLength measurement units - 'L'\nVolume measurement units - 'V'\nTime mesurement units - 'T'\nGo back - 'B'" << endl;
	cout << "Enter the selected character - ";
	cin >> measurement_unit_converter_select;
	switch(measurement_unit_converter_select){
		case 'W':
		case 'w':
			weightMeasurementUnitsSelect(measurement_unit_converter_select);
			break;
		case 'L':
		case 'l':
			lenghtMeasurementUnitsSelect(measurement_unit_converter_select);
			break;
		case 'V':
		case 'v':
			volumeMeasurementUnitsSelect(measurement_unit_converter_select);
			break;
		case 'T':
		case 't':
			timeMeasurementUnitsSelect(measurement_unit_converter_select);
			break;
		case 'B':
		case 'b':
			arithmeticSelect(measurement_unit_converter_select);
			break;
		default:
			cout << "\nWrong character!" << endl;
			measurementUnitsConverterSelect(measurement_unit_converter_select);
			break;
	}
}

	// Make the weight measurement units choice
void weightMeasurementUnitsSelect(char weight_measurement_units_select){
	cout << "\nSelect what you want!" << endl;
	cout << "Tons to Kilogram - 'T'\nKilogram to Tons - 'K'\nTons to Gram - 'R'\nGram to Tons - 'G'\nKilogram to Gram - 'J'\nGram to Kilogram - 'H'\nGo back - 'B'" << endl;
	cout << "Enter the selected character - ";
	cin >> weight_measurement_units_select;
	switch(weight_measurement_units_select){
		case 'T':
		case 't':
			Weight object;
			object.tons_size();
			cout << object.size << " Tons = " << object.get_tons_to_kilogram() << " Kilogram" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> weight_measurement_units_select;
			switch(weight_measurement_units_select){
				case 'O':
				case 'o':
					firstSelect(weight_measurement_units_select);
					break;
				case 'B':
				case 'b':
					weightMeasurementUnitsSelect(weight_measurement_units_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'K':
		case 'k':
			Weight object1;
			object1.kilogram_size();
			cout << object1.size << " Kilogram = " << object1.get_kilogram_to_tons() << " Tons" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> weight_measurement_units_select;
			switch(weight_measurement_units_select){
				case 'O':
				case 'o':
					firstSelect(weight_measurement_units_select);
					break;
				case 'B':
				case 'b':
					weightMeasurementUnitsSelect(weight_measurement_units_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}	
			break;
		case 'R':
		case 'r':
			Weight object2;
			object2.tons_size();
			cout << object2.size << " Tons = " << object2.get_tons_to_gram() << " Gram" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> weight_measurement_units_select;
			switch(weight_measurement_units_select){
				case 'O':
				case 'o':
					firstSelect(weight_measurement_units_select);
					break;
				case 'B':
				case 'b':
					weightMeasurementUnitsSelect(weight_measurement_units_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}	
			break;
		case 'G':
		case 'g':
			Weight object3;
			object3.gram_size();
			cout << object3.size << " Gram = " << object3.get_gram_to_tons() << " Tons" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> weight_measurement_units_select;
			switch(weight_measurement_units_select){
				case 'O':
				case 'o':
					firstSelect(weight_measurement_units_select);
					break;
				case 'B':
				case 'b':
					weightMeasurementUnitsSelect(weight_measurement_units_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'J':
		case 'j':	
			Weight object4;
			object4.kilogram_size();
			cout << object4.size << " Kilogram = " << object4.get_kilogram_to_gram() << " Gram" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> weight_measurement_units_select;
			switch(weight_measurement_units_select){
				case 'O':
				case 'o':
					firstSelect(weight_measurement_units_select);
					break;
				case 'B':
				case 'b':
					weightMeasurementUnitsSelect(weight_measurement_units_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}	
			break;
		case 'H':
		case 'h':
			Weight object5;
			object5.gram_size();
			cout << object5.size << " Gram = " << object5.get_gram_to_kilogram() << " Kilogram" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> weight_measurement_units_select;
			switch(weight_measurement_units_select){
				case 'O':
				case 'o':
					firstSelect(weight_measurement_units_select);
					break;
				case 'B':
				case 'b':
					weightMeasurementUnitsSelect(weight_measurement_units_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'B':
		case 'b':	
			measurementUnitsConverterSelect(weight_measurement_units_select);
			break;
		default:
			cout << "\nWrong character!" << endl;
			weightMeasurementUnitsSelect(weight_measurement_units_select);
			break;
	}
}

	// Make the length measurement units choice
void lenghtMeasurementUnitsSelect(char length_measurement_unit_select){
	cout << "\nSelect what you want!" << endl;
	cout << "Kilometers to Meter - 'Q'\nMeters to Kilometer - 'W'\nKilometers to Centimeter - 'E'\nCentimeter to Kilometer - 'R'\nKilometer to Millimeter - 'T'\nMillimeter to Kilometer - 'Y'\nMeter to Centimeter - 'U'\nCentimeter to Meter - 'I'\nMeter to Millimeter - 'O'\nMillimeter to Meter - 'P'\nCentimeter to Millimeter - 'N'\nMillimeter to Centimeter - 'M'\nGo back - 'B'" << endl;
	cout << "Enter the selected character - ";
	cin >> length_measurement_unit_select;
	switch(length_measurement_unit_select){
		case 'Q':
		case 'q':
			Length object;
			object.kilometer_size();
			cout << object.size << " Kilometer = " << object.get_kilometer_to_meter() << " Meter" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> length_measurement_unit_select;
			switch(length_measurement_unit_select){
				case 'O':
				case 'o':
					firstSelect(length_measurement_unit_select);
					break;
				case 'B':
				case 'b':
					lenghtMeasurementUnitsSelect(length_measurement_unit_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'W':
		case 'w':
			Length object1;
			object1.meter_size();
			cout << object1.size << " Meter = " << object1.get_meter_to_kilometer() << " Kilometer" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> length_measurement_unit_select;
			switch(length_measurement_unit_select){
				case 'O':
				case 'o':
					firstSelect(length_measurement_unit_select);
					break;
				case 'B':
				case 'b':
					lenghtMeasurementUnitsSelect(length_measurement_unit_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'E':
		case 'e':	
			Length object2;
			object2.kilometer_size();
			cout << object2.size << " Kilometer = " << object2.get_kilometer_to_centimeter() << " Centimeter" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> length_measurement_unit_select;
			switch(length_measurement_unit_select){
				case 'O':
				case 'o':
					firstSelect(length_measurement_unit_select);
					break;
				case 'B':
				case 'b':
					lenghtMeasurementUnitsSelect(length_measurement_unit_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'R':
		case 'r':
			Length object3;
			object3.centimeter_size();
			cout << object3.size << " Centimeter = " << object3.get_centimeter_to_kilometer() << " Kilometer" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> length_measurement_unit_select;
			switch(length_measurement_unit_select){
				case 'O':
				case 'o':
					firstSelect(length_measurement_unit_select);
					break;
				case 'B':
				case 'b':
					lenghtMeasurementUnitsSelect(length_measurement_unit_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'T':
		case 't':
			Length object4;
			object4.kilometer_size();
			cout << object4.size << " Kilometer = " << object4.get_kilometer_to_millimeter() << " Millimeter" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> length_measurement_unit_select;
			switch(length_measurement_unit_select){
				case 'O':
				case 'o':
					firstSelect(length_measurement_unit_select);
					break;
				case 'B':
				case 'b':
					lenghtMeasurementUnitsSelect(length_measurement_unit_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}	
			break;
		case 'Y':
		case 'y':
			Length object5;
			object5.millimeter_size();
			cout << object5.size << " Millimeter = " << object5.get_millimeter_to_kilometer() << " Kilometer" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> length_measurement_unit_select;
			switch(length_measurement_unit_select){
				case 'O':
				case 'o':
					firstSelect(length_measurement_unit_select);
					break;
				case 'B':
				case 'b':
					lenghtMeasurementUnitsSelect(length_measurement_unit_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}	
			break;
		case 'U':
		case 'u':
			Length object6;
			object6.meter_size();
			cout << object6.size << " Meter = " << object6.get_meter_to_centimeter() << " Centimeter" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> length_measurement_unit_select;
			switch(length_measurement_unit_select){
				case 'O':
				case 'o':
					firstSelect(length_measurement_unit_select);
					break;
				case 'B':
				case 'b':
					lenghtMeasurementUnitsSelect(length_measurement_unit_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'I':
		case 'i':	
			Length object7;
			object7.centimeter_size();
			cout << object7.size << " Centimeter = " << object7.get_centimeter_to_meter() << " Meter" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> length_measurement_unit_select;
			switch(length_measurement_unit_select){
				case 'O':
				case 'o':
					firstSelect(length_measurement_unit_select);
					break;
				case 'B':
				case 'b':
					lenghtMeasurementUnitsSelect(length_measurement_unit_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}	
			break;
		case 'O':
		case 'o':
			Length object8;
			object8.meter_size();
			cout << object8.size << " Meter = " << object8.get_meter_to_millimeter() << " Millimeter" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> length_measurement_unit_select;
			switch(length_measurement_unit_select){
				case 'O':
				case 'o':
					firstSelect(length_measurement_unit_select);
					break;
				case 'B':
				case 'b':
					lenghtMeasurementUnitsSelect(length_measurement_unit_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'P':
		case 'p':	
			Length object9;
			object9.millimeter_size();
			cout << object9.size << " Millimeter = " << object9.get_millimeter_to_meter() << " Meter" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> length_measurement_unit_select;
			switch(length_measurement_unit_select){
				case 'O':
				case 'o':
					firstSelect(length_measurement_unit_select);
					break;
				case 'B':
				case 'b':
					lenghtMeasurementUnitsSelect(length_measurement_unit_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}	
			break;
		case 'N':
		case 'n':
			Length object10;
			object10.centimeter_size();
			cout << object10.size << " Centimeter = " << object10.get_centimeter_to_millimeter() << " Millimeter" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> length_measurement_unit_select;
			switch(length_measurement_unit_select){
				case 'O':
				case 'o':
					firstSelect(length_measurement_unit_select);
					break;
				case 'B':
				case 'b':
					lenghtMeasurementUnitsSelect(length_measurement_unit_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'M':
		case 'm':	
			Length object11;
			object11.millimeter_size();
			cout << object11.size << " Millimeter = " << object11.get_millimeter_to_centimeter() << " Centimeter" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> length_measurement_unit_select;
			switch(length_measurement_unit_select){
				case 'O':
				case 'o':
					firstSelect(length_measurement_unit_select);
					break;
				case 'B':
				case 'b':
					lenghtMeasurementUnitsSelect(length_measurement_unit_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'B':
		case 'b':	
			measurementUnitsConverterSelect(length_measurement_unit_select);
			break;
		default:
			cout << "\nWrong character!" << endl;
			lenghtMeasurementUnitsSelect(length_measurement_unit_select);
			break;
	}
}

	// Make the volume measurement units choice
void volumeMeasurementUnitsSelect(char volume_measurement_units_select){
	cout << "\nSelect what you want!" << endl;
	cout << "Liter to Mililiter - 'L'\nMililiter to Liter - 'M'\nGo back - 'B'" << endl;
	cout << "Enter the selected character - ";
	cin >> volume_measurement_units_select;
	switch(volume_measurement_units_select){
		case 'L':
		case 'l':
			Volume object;
			object.liter_size();
			cout << object.size << " Liter = " << object.get_liter_to_milliliter() << " Milliliter" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> volume_measurement_units_select;
			switch(volume_measurement_units_select){
				case 'O':
				case 'o':
					firstSelect(volume_measurement_units_select);
					break;
				case 'B':
				case 'b':
					volumeMeasurementUnitsSelect(volume_measurement_units_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'M':
		case 'm':
			Volume object1;
			object1.milliliter_size();
			cout << object1.size << " Milliliter = " << object1.get_milliliter_to_liter() << " Liter" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> volume_measurement_units_select;
			switch(volume_measurement_units_select){
				case 'O':
				case 'o':
					firstSelect(volume_measurement_units_select);
					break;
				case 'B':
				case 'b':
					volumeMeasurementUnitsSelect(volume_measurement_units_select);
					break;
				default:
					cout << "Program is suspended" << endl;
					break;
			}
			break;
		case 'B':
		case 'b':	
			measurementUnitsConverterSelect(volume_measurement_units_select);
			break;
		default:
			cout << "\nWrong character!" << endl;
			volumeMeasurementUnitsSelect(volume_measurement_units_select);
			break;
	}
}

	// Make the time measurement units choice
void timeMeasurementUnitsSelect(char time_measurement_units_select){
	cout << "\nSelect what you want!" << endl;
	cout << "Hour to Minutes - 'H'\nMinutes to Hour -'G'\nHour to Second - 'J'\nSecond to Hour - 'S'\nMinutes to Second - 'D'\nSecond to Minutes - 'F'\nGo back - 'B'" << endl;
	cout << "Enter the selected character - ";
	cin >> time_measurement_units_select;
	switch(time_measurement_units_select){
		case 'H':
		case 'h':
			Time object;
			object.hour_size();
			cout << object.size << " Hour = " << object.get_hour_to_minute() << " Minute" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> time_measurement_units_select;
			switch(time_measurement_units_select){
				case 'O':
				case 'o':
					firstSelect(time_measurement_units_select);
					break;
				case 'B':
				case 'b':
					timeMeasurementUnitsSelect(time_measurement_units_select);
				default:
					cout << "Program is suspended" << endl;
			}	
			break;
		case 'G':
		case 'g':
			Time object1;
			object1.minute_size();
			cout << object1.size << " Minute = " << object1.get_minute_to_hour() << " Hour" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> time_measurement_units_select;
			switch(time_measurement_units_select){
				case 'O':
				case 'o':
					firstSelect(time_measurement_units_select);
					break;
				case 'B':
				case 'b':
					timeMeasurementUnitsSelect(time_measurement_units_select);
				default:
					cout << "Program is suspended" << endl;
			}
			break;
		case 'J':
		case 'j':		
			Time object2;
			object2.hour_size();
			cout << object2.size << " Hour = " << object2.get_hour_to_second() << " Second" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> time_measurement_units_select;
			switch(time_measurement_units_select){
				case 'O':
				case 'o':
					firstSelect(time_measurement_units_select);
					break;
				case 'B':
				case 'b':
					timeMeasurementUnitsSelect(time_measurement_units_select);
				default:
					cout << "Program is suspended" << endl;
			}
			break;
		case 'S':
		case 's':	
			Time object3;
			object3.second_size();
			cout << object3.size << " Second = " << object3.get_second_to_hour() << " Hour" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> time_measurement_units_select;
			switch(time_measurement_units_select){
				case 'O':
				case 'o':
					firstSelect(time_measurement_units_select);
					break;
				case 'B':
				case 'b':
					timeMeasurementUnitsSelect(time_measurement_units_select);
				default:
					cout << "Program is suspended" << endl;
			}	
			break;
		case 'D':
		case 'd':
			Time object4;
			object4.minute_size();
			cout << object4.size << " Minute = " << object4.get_minute_to_second() << " Second" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> time_measurement_units_select;
			switch(time_measurement_units_select){
				case 'O':
				case 'o':
					firstSelect(time_measurement_units_select);
					break;
				case 'B':
				case 'b':
					timeMeasurementUnitsSelect(time_measurement_units_select);
				default:
					cout << "Program is suspended" << endl;
			}	
			break;
		case 'F':
		case 'f':	
			Time object5;
			object5.second_size();
			cout << object5.size << " Second = " << object5.get_second_to_minute() << " Minute" << endl;
			cout << "\nPlease tell me what you want now!" << endl;
			cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
			cout << "Enter the selected character - ";
			cin >> time_measurement_units_select;
			switch(time_measurement_units_select){
				case 'O':
				case 'o':
					firstSelect(time_measurement_units_select);
					break;
				case 'B':
				case 'b':
					timeMeasurementUnitsSelect(time_measurement_units_select);
				default:
					cout << "Program is suspended" << endl;
			}		
			break;
		case 'B':
		case 'b':
			measurementUnitsConverterSelect(time_measurement_units_select);
			break;
		default:
			cout << "\nWrong character!" << endl;
			timeMeasurementUnitsSelect(time_measurement_units_select);
			break;
	}
}

	// Make the equation choice
void equationSelect(char equation_select){
	cout << "\nSelect what you want!" << endl;
	cout << "Linear equation - 'L'\nQuadratic equation - 'Q'\nGo back - 'B'" << endl;
	cout << "Enter the selected character - ";
	cin >> equation_select;
	switch(equation_select){
		case 'L':
		case 'l':
			cout << "\nWe have 2 type linear equation, please select which you want!" << endl;
			cout << "1. ax + b = c - 'F'\n2. ax = b - 'S'\nGo back - 'B'" << endl;
			cout << "Enter the selected character - ";
			cin >> equation_select;
			switch(equation_select){
				case 'F':
				case 'f':
					LinearEquation object;
					object.first_linear_equation();
					cout << "X = " << object.get_first_equation() << endl;
					cout << "\nPlease tell me what you want now!" << endl;
					cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
					cout << "Enter the selected character - ";
					cin >> equation_select;
					switch(equation_select){
						case 'O':
						case 'o':
							firstSelect(equation_select);
							break;
						case 'B':
						case 'b':
							equationSelect(equation_select);
							break;
						default:
							cout << "Program is suspended" << endl;
							break;
					}
					break;
				case 'S':
				case 's':
					LinearEquation object1;
					object1.second_linear_equation();
					cout << "X = " << object1.get_second_equation() << endl;
					cout << "\nPlease tell me what you want now!" << endl;
					cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
					cout << "Enter the selected character - ";
					cin >> equation_select;
					switch(equation_select){
						case 'O':
						case 'o':
							firstSelect(equation_select);
							break;
						case 'B':
						case 'b':
							equationSelect(equation_select);
							break;
						default:
							cout << "Program is suspended" << endl;
							break;
					}	
					break;
				case 'B':
				case 'b':
					equationSelect(equation_select);
					break;
				default:
					cout << "\nWrong character!" << endl;
					equationSelect(equation_select);
					break;
			}
			break;
		case 'Q':
		case 'q':
			cout <<	"\nWe have 3 type quadratic equation, please select which you want!" << endl;
			cout << " '^2' - means squared!, != - means no equal" << endl;
			cout << "1. ax^2 + bx + c = 0, a != 0 - 'F'\n2. ax^2 + bx = 0, a != 0 - 'S'\n3. ax^2 = 0, a != 0 - 'T'\nGo back - 'B'" << endl;
			cout << "Enter the selected character - ";
			cin >> equation_select;
			switch(equation_select){
				case 'F':
				case 'f':
					QuadraticEquation object;
					object.first_quadratic_equation();
					cout << "X1 = " << object.get_x1_first_quadratic_equation() << endl;
					cout << "X2 = " << object.get_x2_first_quadratic_equation() << endl;
					cout << "\nPlease tell me what you want now!" << endl;
					cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
					cout << "Enter the selected character - ";
					cin >> equation_select;
					switch(equation_select){
						case 'O':
						case 'o':
							firstSelect(equation_select);
							break;
						case 'B':
						case 'b':
							equationSelect(equation_select);
							break;
						default:
							cout << "Program is suspended" << endl;
							break;
					}
					break;
				case 'S':
				case 's':
					QuadraticEquation object1;
					object1.second_quadratic_equation();
					cout << "X = 0 or X = " << object1.get_x_second_quadratic_equation() << endl;
					cout << "\nPlease tell me what you want now!" << endl;
					cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
					cout << "Enter the selected character - ";
					cin >> equation_select;
					switch(equation_select){
						case 'O':
						case 'o':
							firstSelect(equation_select);
							break;
						case 'B':
						case 'b':
							equationSelect(equation_select);
							break;
						default:
							cout << "Program is suspended" << endl;
							break;
					}
					break;
				case 'T':
				case 't':
					QuadraticEquation object2;
					object2.third_quadratic_equation();
					cout << "X = 0" << endl;
					cout << "\nPlease tell me what you want now!" << endl;
					cout << "Start over - 'O'\nGo back - 'B'\nStop program - 'S'" << endl;
					cout << "Enter the selected character - ";
					cin >> equation_select;
					switch(equation_select){
						case 'O':
						case 'o':
							firstSelect(equation_select);
							break;
						case 'B':
						case 'b':
							equationSelect(equation_select);
							break;
						default:
							cout << "Program is suspended" << endl;
							break;
					}
					break;
				case 'B':
				case 'b':
					equationSelect(equation_select);
					break;
				default:
					cout << "\nWrong character!" << endl;
					equationSelect(equation_select);
					break;
			}
			break;
		case 'B':
		case 'b':
			arithmeticSelect(equation_select);
			break;
		default:
			equationSelect(equation_select);
			break;
	}
	
}