main.c

#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

typedef struct {
	int result;
	int size;
	int numbers[];
} calc_t;

typedef struct {
	pthread_t thread;
	char *name;
	void *(*fn)(void*);
	int expected;
	calc_t *data;
} test_fn;

void *average(void *data);
void *min(void *data);
void *max(void *data);

int main(void) {
	test_fn threads[] = {
		{ .fn = average, .expected = 82, .name = "average" },
		{ .fn = max, .expected = 95, .name = "max" },
		{ .fn = min, .expected = 72, .name = "min" }
	};
	
	int numbers[] = {90,81,78,95,79,72,85};

	for (int i = 0; i < sizeof(threads)/sizeof(threads[0]); ++i) {
		threads[i].data = malloc(sizeof(calc_t) + sizeof(numbers));
		memcpy(&threads[i].data->numbers, numbers, sizeof(numbers));
		threads[i].data->size = sizeof(numbers)/sizeof(numbers[0]);

		int result = pthread_create(&(threads[i].thread), NULL, threads[i].fn, (void*)(threads[i].data));

		//shitty error handling.
		if (result)
			fprintf(stderr, "pthread_create[%d] returned %d\n", i, result);
	}

	for (int i = 0; i < sizeof(threads)/sizeof(threads[0]); ++i) {
		int retval;
		int result = pthread_join(threads[i].thread, NULL);
		//shitty error handling.
		if (result) {
			fprintf(stderr, "pthread_join[%d] returned %d\n", i, result);
		} else {
			printf("[%s] expected: %d; actual: %d\n", threads[i].name, threads[i].expected, threads[i].data->result);
		}
	}

	return 0;
}

void *average(void *data) {
	calc_t *job = (calc_t*)data;

	int result = 0;
	for (int i = 0; i < job->size; ++i) {
		result += job->numbers[i];
	}

	job->result = result/job->size;

	pthread_exit(0);
}

void *min(void *data) {
	calc_t *job = (calc_t*)data;

	int result;
	for (int i = 0; i < job->size; ++i) {
		if (job->numbers[i] < result || i == 0)
			result = job->numbers[i];
	}

	job->result = result;

	pthread_exit(0);
}

void *max(void *data) {
	calc_t *job = (calc_t*)data;

	int result;
	for (int i = 0; i < job->size; ++i) {
		if (job->numbers[i] > result || i == 0)
			result = job->numbers[i];
	}

	job->result = result;

	pthread_exit(0);
}