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

/*
 * program to find the average value of a set of random numbers
 *
 * usage: avg-nothread count
 *
 * where count is the number of random values to generate
 */

char *Usage = "usage: avg-nothread count";

#define RAND() (drand48()) /* basic Linux random number generator */

int main(int argc, char **argv)
{
	int i;
	int n;
	double *data;
	double sum;
	int count;

	/*
	 * santity check the arguments
	 */
	if(argc <= 1) {
		fprintf(stderr,"must specify count\n");
		fprintf(stderr,"%s",Usage);
		exit(1);
	}

	count = atoi(argv[1]);	/* count is first argument */ 

	if(count <= 0) {
		fprintf(stderr,"invalid count %d\n",count);
		exit(1);
	}

	/*
	 * make an array large enough to hold #count# doubles
	 */
	data = (double *)malloc(count * sizeof(double));
	if(data == NULL) {
		exit(1);
	}

	/*
	 * pick a bunch of random numbers
	 */
	for(i=0; i < count; i++) {
		data[i] = RAND();
	}

	/*
	 * now scan through them and compute the sum
	 */
	sum = 0;
	for(i=0; i < count; i++) {
		sum += data[i];
	}

	printf("the average over %d random numbers on (0,1) is %f\n",
			count, sum/(double)count);

	free(data);

	return(0);
}