Examples of Function Declarations

The following example defines the function absolute with the return type double. Because this is a non-integer return type, absolute is declared prior to the function call.

#include <stdio.h>

double absolute(double);

int main(void)
{
   double f = -3.0;

   printf("absolute number = %lf\n", absolute(f));
}

double absolute(double number)
{
   if (number < 0.0)
      number = -number;

   return number;
}

The following example defines the function absolute with the return type void. Within the function main, absolute is declared with the return type void.

#include <stdio.h>

int main(void)
{
   void absolute(float);
   float f = -8.7;

   absolute(f);
}

void absolute(float number)
{
   if (number < 0.0)
      number = -number;

   printf("absolute number = %f\n", number);
}

Functions
Function Calls

main() Function
Function Declarations
Function Definitions
Examples of Function Calls
Example of the main() Function
Examples of Function Definitions