/* Program illustrating a function prototype near the start of the code
   and the full function definition near the end.
*/

#include <stdio.h>

/* function to add 2 to a value and return the result */
double add2 (double value);   // function prototype, with semi-colon at end


int main ()
{
  printf ("program illustrating a function prototype\n");
  int x = 5;
  double y = add2(x);         // function used

  printf ("x = %d, y = %lf\n", x, y);

  return 0;
}

/* function to add 2 to a value and return the result */
double add2 (double value)   // function details given here
{
   return 2.0 + value;
}