Find the diameter, circumference, and area of the circle using functions.

#include <stdio.h>
#include <math.h>


///Calculate diameter of circle whose num is given
double getDiameter(double num)
{
    return (2 * num);
}
 //Calculate circumference of circle whose num is given
double getCircumference(double num)
{
    return (2 * M_PI * num); // M_PI = PI = 3.14 ...
}
 //Find area of circle whose num is given

double getArea(double num)
{
    return (M_PI * num * num); // M_PI = PI = 3.14 ...
}

int main()
{
    float num, dia, circ, area;

    /* Input num of circle from user */
    printf("Enter num of circle: ");
    scanf("%f", &num);

    dia = getDiameter(num);      
    circ = getCircumference(num);
    area = getArea(num);          

    printf("Diameter of the circle = %.2f units\n", dia);
    printf("Circumference of the circle = %.2f units\n", circ);
    printf("Area of the circle = %.2f sq. units", area);

    return 0;
}


Output

Enter num of circle : 5
Diameter of the circle = 10.00 units
Circumference of the circle = 31.42 units
Area of the circle = 78.54 sq.units