#include <stdio.h>

//Defining the value of pi upto 6 decimal places

#define pi 3.141592

int main()

{

    float radius;

    printf("Enter Radius of Circle:\n");

    scanf("%f",&radius);

    // Calculate the area of the circle

    float area=pi*radius*radius;

    // Print the area of the circle, rounded to two decimal places

    printf("The area of Circle with radius %0.2f is: %0.2f",radius,area);

    return 0;

}

/*

 * C Program to Find Area of Parallelogram

 */

#include <stdio.h>

int main()

{

    float base, altitude;

    float area;

    printf("Enter base and altitude of the given Parallelogram: \n ");

    scanf("%f%f", &base, &altitude);

    area = base * altitude;

    printf("Area of Parallelogram is: %.3f\n", area);

    return 0;

}

/*

 * C program to find the areas of different geometrical shapes such as

 * circle, square, rectangle etc using switch statements.

 */

#include <stdio.h>

void main()

{

    int fig_code;

    float side, base, length, breadth, height, area, radius;

    printf("-------------------------\n");

    printf(" 1 --> Circle\n");

    printf(" 2 --> Rectangle\n");

    printf(" 3 --> Triangle\n");

    printf(" 4 --> Square\n");

    printf("-------------------------\n");

    printf("Enter the Figure code\n");

    scanf("%d", &fig_code);

    switch(fig_code)

    {

    case 1:

        printf("Enter the radius\n");

        scanf("%f", &radius);

        area = 3.142 * radius * radius;

        printf("Area of a circle = %f\n", area);

        break;

    case 2:

        printf("Enter the breadth and length\n");

        scanf("%f %f", &breadth, &length);

        area = breadth * length;

        printf("Area of a Reactangle = %f\n", area);

        break;

    case 3:

        printf("Enter the base and height\n");

        scanf("%f %f", &base, &height);

        area = 0.5 * base * height;

        printf("Area of a Triangle = %f\n", area);

        break;

    case 4:

        printf("Enter the side\n");

        scanf("%f", &side);

        area = side * side;

        printf("Area of a Square=%f\n", area);

        break;

    default:

        printf("Error in figure code\n");

        break;

    }

}

/*

 * C Program to Find the Volume and Surface Area of cylinder

 */

#include <stdio.h>

#include <math.h>

int main()

{

    float radius, height;

    float surface_area, volume;

    printf("Enter  value for  radius and height of a cylinder : \n");

    scanf("%f%f", &radius, &height);

    surface_area = 2 * (22 / 7) * radius * (radius + height);

    volume = (22 / 7) * radius * radius * height;

    printf("Surface area of cylinder is: %.3f", surface_area);

    printf("\n Volume of cylinder is : %.3f", volume);

    return 0;

}

*

 * C Program to Find the Perimeter of a Circle, Rectangle and Triangle

 */

#include <stdio.h>

#include <math.h>

int main()

{

    float radius, length, width, a, b, c, height;

    int n;

    float perimeter;

    //Perimeter of rectangle

    printf(" \n Perimeter of rectangle \n");

    printf("---------------------------\n");

    printf("\n Enter width and length of the rectangle : ");

    scanf("%f%f", &width,& length);

    perimeter = 2 * (width + length);

    printf("Perimeter of rectangle is: %.3f", perimeter);

    //Perimeter of triangle

    printf("\n Perimeter of triangle n");

    printf("---------------------------n");

    printf("\n Enter the size of all sides of the triangle : ");

    scanf("%f%f%f", &a, &b, &c);

    perimeter = a + b + c;

    printf("Perimeter of triangle is: %.3f", perimeter);

    //Perimeter of circle

    printf(" \n Perimeter of circle \n");

    printf("---------------------------\n");

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

    scanf("%f", &radius);

    perimeter = 2 * (22 / 7) * radius;

    printf("Perimeter of circle is: %.3f", perimeter);

    //Perimeter of equilateral triangle

    printf(" \n Perimeter of equilateral triangle \n");

    printf("---------------------------\n");

    printf("\n Enter any side of the equilateral triangle : ");

    scanf("%f", &a);

    perimeter = 3 * a;

    printf("Perimeter of equilateral triangle is: %.3f", perimeter);

    //Perimeter of right angled triangle

    printf(" \n Perimeter of right angled triangle \n");

    printf("---------------------------\n");

    printf("\n Enter the width and height of the right angled triangle : ");

    scanf("%f%f", &width, &height);

    perimeter = width + height + sqrt(width * width + height * height);

    printf("Perimeter of right angled triangle is: %.3f", perimeter);

    return 0;

}