Threads Creation and Execution Example

thread_example.c

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

void initArray(int* array, int N)
{
    int i = 0;
    for(i = 0; i < N; i++)
    {
        array[i] = (int)random();
    }
}

struct ThreadArgs 
{
    int* A;
    int* B;
    int* C;
    int index;
};

void* threadFunc(void* arg)
{
    struct ThreadArgs* args = (struct ThreadArgs*)arg;
    int index = args->index;

    args->C[index] = args->A[index] + args->B[index];
    return NULL;
}

void printArray(int* array, int N)
{
    int i = 0;
    for(i = 0; i < N; i++)
    {
        printf("%010d ", array[i]);
    }
    printf("\n");
}

int main() 
{
    int N;
    int* A = NULL;
    int* B = NULL;
    int* C = NULL;
    int i = 0;

    struct ThreadArgs* args = NULL;
    pthread_t* threads;

    printf("Input array size N: ");
    scanf("%d", &N);

    A = (int*)malloc(N * sizeof(int));
    B = (int*)malloc(N * sizeof(int));
    C = (int*)malloc(N * sizeof(int));

    args = (struct ThreadArgs*)malloc(N * sizeof(struct ThreadArgs));
    threads = (pthread_t*)malloc(N * sizeof(pthread_t));

    initArray(A, N);
    initArray(B, N);

    for(i = 0; i < N; i++)
    {
        args[i].A = A;
        args[i].B = B;
        args[i].C = C;
        args[i].index = i;

        pthread_create(&threads[i], NULL, threadFunc, &args[i]);
    }

    for(i = 0; i < N; i++)
    {
        pthread_join(threads[i], NULL);
    }

    printArray(A, N);
    printArray(B, N);
    printArray(C, N);

    free(A);
    free(B);
    free(C);
    free(args);
    free(threads);

    return 0;
}