Find out the Area of circle by user input in c Programming.

Find out the Area of circle by user input in c Programming.

Theory : First we have to take a variable r in data type int or float as your wish .Now you have to set a veriable in  data type float (pi=3.1416), and  you take  a float type  variable name area .Now you have to take input form user by using (

printf("Enter the value of r :");

    scanf("%d",&r);

)

After doing this things you hae to apply the theory of area of circle (area =pi*r*r). after that print the  area veriable.

Source code : 

                      #include<stdio.h>

int main()

{

    int r;

    float area ,pi=3.1416;

    printf("Enter the value of r :");

    scanf("%d",&r);

    area =pi*r*r;

    printf("Area of circle is =%f",area);

    return 0;

}

Output :

Enter the value of r :5

Area of circle is =78.540001