Perimeter and Area

public class Checkvalidate {

    private Scanner scanner;

    public Checkvalidate() {
        scanner = new Scanner(System.in);
    }

    public double getDoubleInput() {
        double Input;
        while (true) {  // Start an infinite loop to keep asking for input until a valid value is provided.
            try {
                Input = Double.parseDouble(scanner.nextLine());  // Read the user's input and parse it as an integer.
                if (Input > 0) {
                    break;
                    // if size > 0 , valid value and loop break 
                } else {
                    System.err.println("You have to input a positive number , Reinpiut : ");
                    // iff size <= 0 , Display notice 
                }
            } catch (NumberFormatException e) {
                System.err.println("Invalid value , Reinput : ");
                // if users input a special character , program will notice to users 
            }
        }
        return Input;
    }

    public boolean isRectangleValid(double width, double length) {
        if (width > length) {
            System.err.println("Invalid Rectangle.");
            return false;
        }
        return true;
    }

    public boolean isTriangleValid(double sideA, double sideB, double sideC) {
        if (sideA + sideB <= sideC || sideA + sideC <= sideB || sideB + sideC <= sideA) {
            System.err.println("Invalid Triangle.");
            return false;
        }
        return true;
    }

}


public class Main {

    public static void main(String[] args) {
        System.out.println("Please input side Width of Rectangle : ");
        Checkvalidate width = new Checkvalidate();
        double Width = width.getDoubleInput();
        System.out.println("Please input side Length of Rectangle : ");
        Checkvalidate length = new Checkvalidate();
        double Length = length.getDoubleInput();

        while (!width.isRectangleValid(Width, Length)) {
            System.out.println("Please input side Width of Rectangle: ");
            Width = width.getDoubleInput();
            System.out.println("Please input side Length of Rectangle: ");
            Length = length.getDoubleInput();
        }


        System.out.println("Please input side radius of Circle :");
        Checkvalidate radius = new Checkvalidate();
        double Radius = radius.getDoubleInput();

        
        System.out.println("Please input side sideA of Triangle :");
        Checkvalidate sideA = new Checkvalidate();
        double SideA = sideA.getDoubleInput();
        System.out.println("Please input side sideB of Triangle :");
        Checkvalidate sideB = new Checkvalidate();
        double SideB = sideB.getDoubleInput();
        System.out.println("Please input side sideA of Triangle :");
        Checkvalidate sideC = new Checkvalidate();
        double SideC = sideC.getDoubleInput();
        while (!sideA.isTriangleValid(SideA, SideB, SideC)) {
            System.out.println("Please input side sideA of Triangle: ");
            SideA = sideA.getDoubleInput();

            System.out.println("Please input side sideB of Triangle: ");
            SideB = sideB.getDoubleInput();

            System.out.println("Please input side sideC of Triangle: ");
            SideC = sideC.getDoubleInput();
        }

        
        System.out.println("-----Rectangle-----");
        Rectangle rectangle = new Rectangle(Width, Length);
        rectangle.printResult();

        System.out.println("-----Circle-----");
        Circle circle = new Circle(Radius);
        circle.printResult();

        System.out.println("-----Triangle-----");
        Triangle triangle = new Triangle(SideA, SideB, SideC);
        triangle.printResult();
    }

}