// fltfunct_64.c  call math routine  double sin(double x) 
#include <stdio.h>
#include <math.h>
int main()
{
  double x = 0.7853975;	// Pi/4 = 45 degrees
  double y;
  y = sin(x);
  printf("y= %e = sin(%e)\n", y, x);
  return 0;
}