/* float_sig.c   find small, big and eps */
#include <stdio.h>

int main(int argc, char * argv[])
{
  double xx, xxp, xxeps;
  float x, xp, eps;
  int i;
  
  printf("float_sig.c running, may die \n");
  printf("type float has about six significant digits \n");
  printf("eps is the smallest positive number added to 1.0f that changes 1.0f\n");
  eps=1.0;
  for(i=1; i<26; i++) /* we know about 24 bits */
  {
    eps=eps/2.0;
    if(1.0f-eps == 1.0f) break;
  }
  eps=2.0*eps;
  printf("type float eps=%16.9E \n", eps);

  x=1.0;
  for(i=1; i<256; i++) /* we know about 8 bits */
  {
    xp=x;
    x=x/2.0;
    if(x == 0.0f) break;
  }
  printf("type float small=%16.9E \n", xp);
  printf("this could be about 1.0E-38, above shows good IEEE floating point\n");
  x=1.0;
  for(i=1; i<256; i++) /* we know about 8 bits */
  {
    xp=x;
    x=x*2.0;
    if(x/2.0!=xp) break;
  }
  printf("type float large=%16.9E \n\n", xp);


  printf("type double has about fifteen significant digits \n");
  xxeps=1.0;
  for(i=1; i<55; i++) /* we know about 52 bits */
  {
    xxeps=xxeps/2.0;
    if(1.0-xxeps == 1.0) break;
  }
  xxeps=2.0*xxeps;
  printf("type double eps=%24.17E \n", xxeps);

  xx=1.0;
  for(i=1; i<4096; i++) /* we know about 11 bits */
  {
    xxp=xx;
    xx=xx/2.0;
    if(xx == 0.0) break;
  }
  printf("type double small=%16.9E \n", xxp);
  printf("this could be about 1.0E-304, above shows good IEEE floating point\n");

  xx=1.0;
  for(i=1; i<4096; i++) /* we know about 11 bits */
  {
    xxp=xx;
    xx=xx*2.0;
    if(xx/2.0!=xxp) break;
  }
  printf("type double large=%16.9E \n", xxp);


  return 0;
}