Question

4. Write a Program in C to calculate the area of a triangle, rectangle or a circle using function depending on the choice entered by the user.
1. Triangle 2. Rectangle 3. Circle 4. Exit
​

Answer 1

$\textsf{\large{\underline{Solution}:}}$

The given problem is solved using language - C.

#include <stdio.h>

void triangleArea(){

   float a,b,c;

       printf("Enter the first side of the triangle: ");

       scanf("%f",&a);

       printf("Enter the second side of the triangle: ");

       scanf("%f",&b);

       printf("Enter the third side of the triangle: ");

       scanf("%f",&c);

       float s,area;

       s=(a+b+c)/2.0;

       area=sqrt(s*(s-a)*(s-b)*(s-c));

       printf("Area of the triangle is %.2f square units.",area);

}

void rectangleArea(){

   float a,b;

       printf("Enter the length of the rectangle: ");

       scanf("%f",&a);

       printf("Enter the breadth of the rectangle: ");

       scanf("%f",&b);

       printf("The area of the rectangle is: %.2f",a*b);

}

void circleArea(){

   float r,a;

   printf("Enter the radius of the circle: ");

   scanf("%f",&r);

   a=3.14159*r*r;

   printf("The area of the circle is: %.2f",a);

}

int main() {

   int c;

   printf("1. Area of a triangle.\n");

   printf("2. Area of a rectangle.\n");

   printf("3. Area of a circle.\n");

   printf("4. Exit.\n\n");

   printf("Enter your choice: ");

   scanf("%d",&c);

   switch(c){

       case 1:

       triangleArea();

       break;

       case 2:

       rectangleArea();

       break;

       case 3:

       circleArea();

       break;

       case 4:

       printf("Program Terminated.");

       break;

       default: printf("Invalid choice.");

   }

   return 0;

}

$\textsf{\large{\underline{Sample I/O}:}}$

#1

1. Area of a triangle.

2. Area of a rectangle.

3. Area of a circle.

4. Exit.

Enter your choice: 1

Enter the first side of the triangle: 5

Enter the second side of the triangle: 4

Enter the third side of the triangle: 3

Area of the triangle is 6.00 square units.

——————————————————————————

#2

1. Area of a triangle.

2. Area of a rectangle.

3. Area of a circle.

4. Exit.

Enter your choice: 2

Enter the length of the rectangle: 10

Enter the breadth of the rectangle: 5

The area of the rectangle is: 50.00

——————————————————————————

#3

1. Area of a triangle.

2. Area of a rectangle.

3. Area of a circle.

4. Exit.

Enter your choice: 3

Enter the radius of the circle: 5.0

The area of the circle is: 78.54

——————————————————————————

#4

1. Area of a triangle.

2. Area of a rectangle.

3. Area of a circle.

4. Exit.

Enter your choice: 4

Program Terminated.

——————————————————————————

#5

1. Area of a triangle.

2. Area of a rectangle.

3. Area of a circle.

4. Exit.

Enter your choice: 10

Invalid choice.