/* example that demonstrates the use of constants */
#include <stdio.h>
#include <math.h>
#define PI 3.141593; 
/*tells the preprocessor to substitute a value for pi */

int main (void)
{
  float const pie = 3.141593;
  float f;
  f = PI;
  printf("Pi = %f\n",f);
  f = pie;
  printf("Pie = %f\n",f);
}