/* Driver for routine poidev */

#include <stdio.h>
#include "nr.h"

#define N 20
#define NPTS 10000
#define ISCAL 200
#define LLEN 50

main()
{
	char txt[LLEN+1];
	long idum=(-13);
	int i,j,k,klim,dist[N+1];
	float xm,dd;

	for (;;) {
		for (j=0;j<=N;j++) dist[j]=0;
		do {
			printf("Mean of Poisson distribution (0.0<x<%d.0) ",N);
			printf("- Negative to end:\n");
			scanf("%f",&xm);
		} while (xm > N);
		if (xm < 0.0) break;
		for (i=1;i<=NPTS;i++) {
			j=(int) (0.5+poidev(xm,&idum));
			if ((j >= 0) && (j <= N)) ++dist[j];
		}
		printf("Poisson-distributed deviate, mean %5.2f of %6d points\n",
			xm,NPTS);
		printf("%5s %8s %10s\n","x","p(x)","graph:");
		for (j=0;j<=N;j++) {
			dd=(float) dist[j]/NPTS;
			for (k=0;k<=LLEN;k++) txt[k]=' ';
			klim=(int) (ISCAL*dd);
			if (klim > LLEN) klim=LLEN;
			for (k=1;k<=klim;k++) txt[k]='*';
			txt[LLEN]='\0';
			printf("%6d %8.4f   %s\n",j,dd,txt);
		}
	}
	return 0;
}