aa

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

float sum = 0;
int n;
int w;
float *random_numbers;

pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;

void* array_sum(void* arg)
{
    int start_index = *(int *) arg;
    float tmp_sum = 0;
    printf("Thread #%ld size=%d\n", pthread_self(), (n/w));
    for (int i = 0; i < n/w; i++)
        tmp_sum += random_numbers[start_index+i];

    pthread_mutex_lock(&mutex);
    sum += tmp_sum;
    pthread_mutex_unlock(&mutex);

    printf("Thread #%ld sum=%f\n", pthread_self(), tmp_sum);
    pthread_exit(NULL);
}

void* array_sum2(void* arg)
{
    int start_index = *(int *) arg;
    float tmp_sum = 0;
    printf("Thread #%ld size=%d\n", pthread_self(), n - (w-1) * (n/w));
    for (int i = 0; i < n - (w-1) * (n/w); i++)
        tmp_sum += random_numbers[start_index+i];

    pthread_mutex_lock(&mutex);
    sum += tmp_sum;
    pthread_mutex_unlock(&mutex);

    printf("Thread #%ld sum=%f\n", pthread_self(), tmp_sum);
    pthread_exit(NULL);
}

int main(int argc, char **argv)
{
	if (argc != 3)
	{
		printf("Nalezy podac dokladnie 2 argumenty do wywolania tego programu!\n");
		exit(-1);
	}
    if (atoi(argv[1]) >= 1000000)
    {
        printf("Za duze n!\n");
        exit(-2);
    }
    if (atoi(argv[2]) < 0 || atoi(argv[2]) > atoi(argv[1]))
    {
        printf("Niepoprawne w!\n");
        exit(-3);
    }

	n = atoi(argv[1]);
	w = atoi(argv[2]);
	random_numbers = malloc(n * sizeof(*random_numbers));

	/* Generate random numbers */
	srand(0);
	for (int i = 0; i < n; i++)
		random_numbers[i] = 1000. * rand() / RAND_MAX;

	/* Args to functions*/
    int arguments[w];
    arguments[0] = 0;
    for (int i = 1; i < w - 1; i++)
        arguments[i] = i*(n/w);
    arguments[w-1] = n - (n - (w-1) * (n/w));
    /* Threads version */
    pthread_t threads_ids[w];
    clock_t start = clock();
    for (int i = 0; i < w-1; i++)
    {
        pthread_create(&threads_ids[i], NULL, array_sum, &arguments[i]);
    }
    pthread_create(&threads_ids[w-1], NULL, array_sum2, &arguments[w-1]);

    for (int i = 0; i < w; i++)
        pthread_join(threads_ids[i], NULL);
    clock_t end = clock();
    printf("w/Threads: sum = %f, time = %f sec \n", sum, ((double) (end - start) / CLOCKS_PER_SEC));


    /* Without threads version */
    sum = 0;
	start = clock();
	for (int i = 0; i < n; i++)
		sum += random_numbers[i];
	end = clock();
	printf("wo/Threads: sum = %f, time = %f sec \n", sum, ((double) (end - start) / CLOCKS_PER_SEC));


	free(random_numbers);
	return 0;
}