ECE426 Lab4

lab4a.c

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

#define NTHREADS 10

void *sum_runner(void *param);

int sum;

int main(int arc, char *argv[])
{
    sum = 0;

    pthread_t threads[NTHREADS];
    void *retvals[NTHREADS];
    int count;
    for (count = 0; count < NTHREADS; ++count)
    {
        if (pthread_create(&threads[count], NULL, sum_runner, count+1) != 0)
        {
            fprintf(stderr, "error: Cannot create thread # %d\n", count);
            break;
        }
    }
    int i;
    for (i = 0; i < count; ++i)
    {
        if (pthread_join(threads[i], &retvals[i]) != 0)
        {
            fprintf(stderr, "error: Cannot join thread # %d\n", i);
        }
    }
    //sleep(1);
    printf("Sum: %d\n", sum);
}

void *sum_runner(void *param)
{
    sum += (int)param;
}

lab4b.c

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

#define N 3
#define NTHREADS N*N

void *mult_runner(void *param);

int m1[N][N] = {
    {1, 2, 3},
    {1, 2, 3},
    {1, 2, 3}
};
int m2[N][N] = {
    {1, 2, 3},
    {1, 2, 3},
    {1, 2, 3}
};
int mo[N][N];

int main(int arc, char *argv[])
{

    pthread_t threads[NTHREADS];
    void *retvals[NTHREADS];
    int count;
    for (count = 0; count < NTHREADS; ++count)
    {
        if (pthread_create(&threads[count], NULL, mult_runner, count) != 0)
        {
            fprintf(stderr, "error: Cannot create thread # %d\n", count);
            break;
        }
    }
    int i;
    for (i = 0; i < count; ++i)
    {
        if (pthread_join(threads[i], &retvals[i]) != 0)
        {
            fprintf(stderr, "error: Cannot join thread # %d\n", i);
        }
    }
    for(i = 0; i < 3; i++){
        for(int j = 0; j < 3; j++){
            printf("%d ", mo[i][j]);
        }
        printf("\n");
    }
}

void *mult_runner(void *param)
{
    int i = (int)param/3;
    int j = (int)param%3;
    mo[i][j] = 0;
    int k;
    for (k = 0; k < N; k++)
        mo[i][j] += m1[i][k]*m2[k][j];
}