Untitled

/**
*
* Solution to course project # 4
* Introduction to programming course
* Faculty of Mathematics and Informatics of Sofia University
* Winter semester 2024/2025
*
* @author Niya Neykova
* @idnumber 5MI0600488
* @compiler GCC
*
* <file with helper functions ›
*
*/

#include <iostream>
#include <vector>
using namespace std;

//getting polynomial's coefficients
vector<double> getCoefficient() {
    int degree;
    cout << "Enter the degree of P(x): " << endl;
    cin >> degree;
    vector<double> coefficients(degree + 1);
    for (int i = degree; i >= 0; i--) {
        cout << "Enter the coefficient before x^" << i << ": ";
        cin >> coefficients[i];
    }

    return coefficients;
}

//adding two polynomials together
vector<double> addPolynomials(vector<double> &polynomial1, vector<double> &polynomial2) {
    int newDegree, degree1, degree2;
    degree1 = polynomial1.size() - 1;
    degree2 = polynomial2.size() - 1;
    if (degree1 >= degree2) newDegree = degree1;
    else newDegree = degree2;

    vector<double> newPolynomial(newDegree + 1);
    for (int i = 0; i <= newDegree; i++) {
        double polynomial1Coeff = 0;
        double polynomial2Coeff = 0;
        if (i < polynomial1.size()) polynomial1Coeff = polynomial1[i];
        else polynomial1Coeff = 0;
        if (i < polynomial2.size()) polynomial2Coeff = polynomial2[i];
        else polynomial2Coeff = 0;

        newPolynomial[i] = polynomial1Coeff + polynomial2Coeff;
    }

    return newPolynomial;
}

//subtracting two polynomials
vector<double> subtractPolynomials(vector<double> &polynomial1, vector<double> &polynomial2) {
    int newDegree, degree1, degree2;
    degree1 = polynomial1.size() - 1;
    degree2 = polynomial2.size() - 1;
    if (degree1 >= degree2) newDegree = degree1;
    else newDegree = degree2;

    vector<double> newPolynomial(newDegree + 1);
    for (int i = 0; i <= newDegree; i++) {
        double polynomial1Coeff = 0;
        double polynomial2Coeff = 0;
        if (i < polynomial1.size()) polynomial1Coeff = polynomial1[i];
        else polynomial1Coeff = 0;
        if (i < polynomial2.size()) polynomial2Coeff = polynomial2[i];
        else polynomial2Coeff = 0;

        newPolynomial[i] = polynomial1Coeff - polynomial2Coeff;
    }

    return newPolynomial;
}

//printing a polynomial
void printPolynomial(vector<double> &coefficients) {
    for (int i = coefficients.size() - 1; i >= 0; i--) {
        if (coefficients[i] != 0) {
            cout << coefficients[i];
            if (i > 0) {
                cout << "x^" << i;
            }
            if (i > 0 && coefficients[i - 1] > 0) {
                cout << " + ";
            }
        }
    }
    cout << endl;
}

int main() {
    int numOfFunc;
    cout << "Welcome to Polynomial Calculator - ";
    cout << "a mini project intended to work with polynomials with rational coefficients." << endl;

    while (true) {
        cout << "Choose one of the following functionalities:" << endl;
        cout << "1) Add polynomials" << endl;
        cout << "2) Subtract polynomials" << endl;
        cout << "3) Multiply polynomials" << endl;
        cout << "4) Divide polynomials" << endl;
        cout << "5) Multiply polynomial by scalar" << endl;
        cout << "6) Find value of polynomial at a given number" << endl;
        cout << "7) Find GCD of two polynomials" << endl;
        cout << "8) Display Vieta's formulas for a given polynomial" << endl;
        cout << "9) Represent a polynomial in powers of (x+a)" << endl;
        cout << "10) Factor polynomial and find its rational roots" << endl;
        cout << "11) Quit program" << endl;
        cout << "Enter your option: " << endl;

        cin >> numOfFunc;
        if (numOfFunc == 11) {
            cout << "Thank you for using me! Goodbye!" << endl;
            break;
        }
        switch (numOfFunc) {
            case 1: {
                cout << "You chose the first functionality!" << endl;
                cout << "Enter Polynomial P(x)" << endl;
                vector<double> polynomial1 = getCoefficient();
                cout << "Enter Polynomial Q(x)" << endl;
                vector<double> polynomial2 = getCoefficient();
                vector<double> sum = addPolynomials(polynomial1, polynomial2);
                cout << "The sum of the polynomials is:" << endl;
                printPolynomial(sum);
            }
            break;
            case 2: {
                cout << "You chose the second functionality!" << endl;
                cout << "Enter Polynomial P(x)" << endl;
                vector<double> polynomial1 = getCoefficient();
                cout << "Enter Polynomial Q(x)" << endl;
                vector<double> polynomial2 = getCoefficient();
                vector<double> subtract = subtractPolynomials(polynomial1, polynomial2);
                cout << "The sum of the polynomials is:" << endl;
                printPolynomial(subtract);
            }
            break;

            default:
                cout << "Invalid input. Try again!" << endl;
        }
    }
    return 0;
}