using System;

​

// Setting up the interface

interface Shape

{

    void getArea(double a, double b);

}

​

// Creating the Rectangle class to implement methods in interface

public class Rectangle : Shape

{

    // setting up rectangle fields

    public double length;

    public double width;

    public double area;

    // setting up method required by interface

    public void getArea(double length, double width)

    {

        area = length * width;

        Console.WriteLine(area);

    }

}

​

// Creating the Triangle class to implement methods in interface

public class Triangle : Shape

{

    // setting up triangle fields

    public double base_t;

    public double height;

    public double area_t;

    // setting up method required by interface

    public void getArea(double base_t, double height)

    {

        area_t = 0.5 * base_t * height;

        Console.WriteLine(area_t);

    }

}

​

public class test

{

    public static void Main()

    {

        // creating instance of rectangle

        Rectangle rectangle1 = new Rectangle();

        rectangle1.length = 3;

        rectangle1.width = 2;

        // testing method for rectangle class

        rectangle1.getArea(rectangle1.length, rectangle1.width);

        // creating instance of triangle

        Triangle triangle1 = new Triangle();

        triangle1.base_t = 3;

        triangle1.height = 2;

        // testing method for rectangle class

        triangle1.getArea(triangle1.base_t, triangle1.height);

    }

}