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

void* print0s(void* arg) {
    while (true)
        printf("0");
}

void* print1s(void* arg) {
    while (true)
        printf("1");
}

int main(int argc, char** argv) {
    pthread_t thd1, thd2;
    
    pthread_create(&thd1, NULL, print0s, NULL);
    pthread_create(&thd2, NULL, print1s, NULL);
    
    void* result;
    
    pthread_join(thd1, &result);
    pthread_join(thd2, &result);
}