multi_stat.c

#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>

/* the list of integers */
int *list;

/* the threads will set these values */
double average;
int maximum;
int minimum;

void *calculate_average(void *param);
void *calculate_maximum(void *param);
void *calculate_minimum(void *param);

int main(int argc, char *argv[])
{
	int i;
	int num_of_args = argc-1;
	pthread_t tid_1;
	pthread_t tid_2;
	pthread_t tid_3;

	/* allocate memory to hold array of integers */
        list = malloc(sizeof(int)*num_of_args);

	for (i = 0; i < num_of_args; i++)
		list[i] = atoi(argv[i+1]);

	/* create the threads */
	pthread_create(&tid_1, NULL, calculate_average, &num_of_args);
	pthread_create(&tid_2, NULL, calculate_maximum, &num_of_args);
	pthread_create(&tid_3, NULL, calculate_minimum, &num_of_args);

	/* wait for the threads to exit */
	pthread_join(tid_3, NULL);

	printf("The average is %f\n", average);
	printf("The maximum is %d\n", maximum);
	printf("The minimum is %d\n", minimum);

	return 0;
}

void *calculate_average(void *param)
{
	double count = *((int *)param);

	int i;
	double sum = list[0];
	for(i = 1; i < count; i++)
		sum += list[i];

	average = sum / count;

	pthread_exit(0);
}

void *calculate_maximum(void *param)
{
	int count = *((int *)param);

	int i;

	maximum = list[0];

	for(i=1; i < count; i++)
		if(list[i] > maximum)
			maximum = list[i];

	pthread_exit(0);
}

void *calculate_minimum(void *param)
{
	int count = *((int *)param);

	int i;

	minimum = list[0];

	for (i=1; i < count; i++)
		if(list[i] < minimum)
			minimum = list[i];

	pthread_exit(0);
}