/* Last edited on 2009-02-10 11:18:37 by stolfi */

/* Tests of various floating-point values, limits, format, sizes. */

#include <stdio.h>
#include <math.h>
#include <values.h>

void dbp(char *s, double x);

void dbp(char *s, double x)
{
  int e;
  double f = frexp(x, &e);
  printf("%-8s = %25.17le  f = %25.17le e = %+d\n", s, x, f, e);
}

int main(int argc, char **argv)
{
  double m = DBL_MAX;
  dbp("m", m);
  dbp("m/8", m/8);
  dbp("8/m", 8/m);
  dbp("1/m", 1/m);
  
  double g = log(m);
  dbp("g", g);
  
  double s = sqrt(m);
  dbp("s", s);
  dbp("1/s", 1/s);
  
  int e;
  double f = frexp(m, &e);
  printf("(f,e) =  %25.17le * 2^{%d}\n",f,e);
  
  double c = 1+2*(1-f);
  dbp("c", c);
  
  int z0 = sizeof(float);
  int z1 = sizeof(double);
  int z2 = sizeof(long double);
  printf("sizes =  %d %d %d bytes\n",z0,z1,z2);
  
  short int t = 0;
  printf("t =      %hd\n",t);
  
  long double N = 1;
  printf("N =      %50.42Le\n",N);
  
  /* Testing the number of matissa bits in a {long double}: */
  long double D = 1;
  int eD = 0;
  long double P, Q;
  do { D = D/2; eD++; P = Q; Q = N + D; } while (Q != N); 
  printf("D =      %50.42Le  eD = %d\n",D, eD);
  printf("P =      %50.42Le\n",P);

  return 0;
}