Fermat near miss finder

fermat.c

/*
   Fermat Near-Miss Finder

   Written by David X. Cohen
   February 3, 1998, 3:24 AM.

   This program generated the equation:

   3987^12 + 4365^12 = 4472^12

   For "The Simpsons" episode "The Wizard of Evergreen Terrace".
   Production code: 5F21
   Original Airdate: September 20, 1998

   HOW TO COMPILE:
   $ gcc fermat.c -o fermat -lm

   This will stop at 5000.
   Increase the UPPER_BOUND if desired.

*/

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

#define UPPER_BOUND 5000.0

#define EVEN(x)  ((((x) / 2.0) == floor((x) / 2.0)) ? 1 : 0)

int main()
{
  double x, y, i, z, az, d, upmin;
  double bigboy;
  int evenx, eveny, evenz;
  upmin = .001;
  bigboy = 9.99 * pow(10.0, 99.0);

  for(x = 2990.0; x <= UPPER_BOUND - 1; x ++)
    {
      printf("[%.0f]", x);

      evenx = EVEN(x);
      for(y = x + 1.0; y <= UPPER_BOUND; y ++)
        {
          eveny = EVEN(y);

          for(i = 7.0; i <= 77.0; i ++)
            {
              z = pow(x, i) + pow(y, i);

              if(z == HUGE_VAL) {
                printf("[*]");
                break;  }

              if(z > bigboy) break;

              z = pow(z, (1.0/i));
              az = floor(z + .5);
              d = z - az;

              if(az == y) break;

              if(d < 0.0) continue;

              evenz = EVEN(az);

              if(evenx == eveny)
                {
                  if(!evenz) continue;
                }
              else if(evenz) continue;

              if(d <= upmin)
                {
                  upmin = d;
                  printf("\n%.1f, %.1f, %.1f, = %13.10f\n", x, y, i, z);
                }
              if(z < (y + 1.0)) break;
            }
        }
    }
  return(1);
}