//this is an implementation of the exercise on p.25 of Landau
//this program will try to determine the machine precision of the
//	running computer system within a factor of 2
//this program will output three columns of ASCII numbers
//	and one can plot them with any graphic package

#include <stdio.h>

long counter;

FILE *outfile;

main()
{
	double eps;
	double one;

	//initializing variables
	eps=1.0;
	counter=0;

	//initializing output date file
	outfile=fopen("machine.dat","w");

	do
	{
		eps=eps/2.0;
		one=1.0+eps;
		counter++;
		fprintf(outfile,"%ld\t%22.18lg\t%lg\n",counter,one,eps);
	}
	while (one > 1.0);
	//this while loop will continue until 'one' is indistinguishable from 1.0
	
	printf("Machine precision reached at %ld step\n",counter);
	printf("\tepslion value is %lg\n",eps);

	return 0;
}