Thread: Why doesn't it works?

The following code correct(er):

Code:

#include <stdlib.h>
#include <stdio.h>
#include <time.h>

#define NUM 100
#define IMAX 10
#define ISEED 777861
#define ISEED1 777862

#define RND() ((double)rand()/(double)RAND_MAX)

int main ()
{

	int i, naccept=0, nreject=0, ntrial=0, c;
	double x[NUM],s[NUM],r[NUM],pi;

	srand( time(NULL) );
	naccept=0; nreject=0; ntrial=0;
	for (i=0; i<NUM; i++)
	{
		x[i]=RND();
	}

	int j;
	double y[NUM];
	//srandom(ISEED1);

	for (j=0; j<NUM; j++)
	{
		y[j]=RND();
	}
	for (c=0; c<NUM; c++)
	{
		r[c]=x[c]*x[c]+y[c]*y[c];
		printf("r=&#37;f\n",r[c]);
		s[c]=r[c]*r[c];
		printf("s[c]=%f\n",s[c]);
		if (s[c]<1.0){
			naccept++;
		}
		else  {
			nreject++;
		}
	}
	ntrial= naccept+nreject;
	printf("naccept=%d   nreject=%d   ntrail=%d\n",naccept,nreject,ntrial);
	pi=4.0*((double)naccept/(double)ntrial);
	printf("pi=%.3f\n",pi);
}

I suggest you update the code because are sure using some non-standard stuff.
It almost produces correct pi (ca 3.04x something I believe).

And only initialize the seed once.