Programming

#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>
#include <string.h>
#define MAX 10
pthread_t thread[2];

void *thread1()
{

    int *a[16];
    int i, n;


    for (i = 0; i < 16; i++)
    {

    n=(size_t) ((rand() * 256.0) / (RAND_MAX + 1.0)) + 1;
        a[i] = (int*)malloc(n);
    if (a[i]==NULL)
        {
            printf("Error allocating memory!");
            exit (1);
        }

       printf("malloc a[%d]\n",i);

    }

    for (i = 16; i > 0; i--)
    {

        n=(size_t) ((rand() * 256.0) / (RAND_MAX + 1.0)) + 1;
        printf("remalloc a[%d]\n",i-1);
        a[i - 1] = (int*)realloc(a[i - 1], n);
    if ( a[i - 1]==NULL)
        {
            printf("Error reallocating memory!");
            exit (1);
        }


    }
    for (i = 0; i < 16; i += 2 )
        free(a[i]);
        printf("free1 a[%d]\n",i);
    for (i = 16; i > 0; i -= 2)
        free(a[i - 1]);
        printf("free2 a[%d]\n",i-1);
        pthread_exit(NULL);
}


void thread_create(void)
{
        int temp,i;
        memset(&thread, 0, sizeof(thread));          //comment1
        /**/
       for (i = 2; i > 0; i--)
{
        if((temp = pthread_create(&thread[i], NULL, thread1, NULL)) != 0)       //comment2
                printf("thread create failed\n");
        else
                printf("thread create\n");
}
}

void thread_wait(void)
{
   int i;
   for (i = 2; i > 0; i--)
{
        if(thread[i] !=0) {                   //comment4
                pthread_join(thread[i],NULL);
                printf("1\n");
        }
}
}

int main()
{

        printf("\n");
        thread_create();
        printf("\n");
        thread_wait();

        return 0;
}

for (i = 2; i > 0; i--)