/*file: hello.c*/
#include <stdio.h>
#include <stdlib.h>
#include <math.h>


double sinfunc(double a);

main(int argc, char* argv[])
{
  double res;
  if (argc < 2) {  /* check command-line argument */
    printf("Usage: %s number\n", argv[0]);  exit(1);
  }
  res = atof(argv[1]);
  printf("Hello from C!\n");
  printf("The sin(%g) = %g", res, sinfunc(res));
}

/*Computes the sin of argument number*/
double sinfunc(double a)
{
  double res;
  res = sin(a);
  return res;
}