#include	<stdio.h>
#include	<stdlib.h> /* for random function parameter */
#define	NR	10000
main()
{
	int	rx, iv[NR], rxmin, rxmax;
	int	i, nstep = 10000;
	int	ir;
	rxmin = -500; rxmax = 500;
	for (i = rxmin; i <= rxmax; i++) iv[i-rxmin] = 0;
		/* iv[] is array for visited frequency */

	rx = 0;
	for (i = 0; i < nstep; i++) {
		ir = rand();	/* built-in random number generator */
		if ((double)ir / RAND_MAX < 0.5) { 
			/* RAND_MAX is built-in parameter */
			rx++; /* move right */
		} else {
			rx--; /* move left */
		}
		iv[rx-rxmin]++;
		/* fprintf(stderr, "%d %d\n", i, rx); */
	}
	for (i = rxmin; i <= rxmax; i++)
		if (iv[i-rxmin] != 0) printf("%5d %5d\n", i, iv[i-rxmin]);
}