You'll need three functions like this :
Code:
float function(float radius)
{
return whatever;
}
You have the formulae, so just plonk in it the function as the return value.
Here's an example:
Code:
float circumference(float radius)
{
return (2*PI*radius);
}
You will also need to declare the functions before main().
Code:
#include <stdio.h>
#include <conio.h>
#define PI 3.14159
float diameter(float radius);
float circumference(float radius);
float area(float radius);
int main()
{
..
..
..
return 0;
}
To print the values in main(), just print the return value of the function, eg.
Code:
printf("circumference = %f", circumference(radius));
Oh, and don't use void main(), use int main() and then return 0 at the end.