/*

fp-value.c

Simple program to test floating point numbers. Input the number of iterations
you want on the command line.

*/

#include <stdlib.h>
#include <stdio.h>
#include <float.h> /* DBL_DIG and LDBL_DIG */

#define INCR 0.4
#define INCR_L 0.4L

int main(int argc, char **argv) {
  double n_d = 0.0;
  double n_dL = 0.0L;
  long double n_ld = 0.0;
  long double n_ldL = 0.0L;
  unsigned long long i, max;
  char *dummy;

  if(argc <= 1) {
    fprintf(stderr, "Usage: %s <number of iterations>\n", argv[0]);
    exit(1);
  }

  max = strtoull(argv[1], &dummy, 10);
  printf("START\n");
  printf("double 0.0 is %.*g\n", DBL_DIG, n_d);
  printf("double 0.0L is %.*g\n", DBL_DIG, n_dL);
  printf("long double 0.0 is %.*Lg\n", LDBL_DIG, n_ld);
  printf("long double 0.0L is %.*Lg\n", LDBL_DIG, n_ldL);
  for(i = 1; i <= max; i++) {
    n_d += INCR;
    n_dL += INCR_L;
    n_ld += INCR;
    n_ldL += INCR_L;
  }
  printf("MIDDLE\n");
  printf("double 0.0 is %.*g\n", DBL_DIG, n_d);
  printf("double 0.0L is %.*g\n", DBL_DIG, n_dL);
  printf("long double 0.0 is %.*Lg\n", LDBL_DIG, n_ld);
  printf("long double 0.0L is %.*Lg\n", LDBL_DIG, n_ldL);
  for(i = 1; i <= max; i++) {
    n_d -= INCR;
    n_dL -= INCR_L;
    n_ld -= INCR;
    n_ldL -= INCR_L;
  }
  printf("END\n");
  printf("double 0.0 is %.*g\n", DBL_DIG, n_d);
  printf("double 0.0L is %.*g\n", DBL_DIG, n_dL);
  printf("long double 0.0 is %.*Lg\n", LDBL_DIG, n_ld);
  printf("long double 0.0L is %.*Lg\n", LDBL_DIG, n_ldL);
}