Thread: help about segmention fault

I always get a segmentation fault, can someone help me to modify. thanks in advance

Code:

#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>
#include <string.h>
#define MAX 10
pthread_t thread[6];

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 = 6; 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 = 6; 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;
}

You should have your debugger attached and when it breaks into the debugger, tell us which line is breaks on.

You're accessing thread out of bounds.

Why did you put this in C++?

Because thread function should be
void *thread1(void *p)

Not
void *thread1()

> I get no segfault. Should that be ok?
No, you just got the other side of the "luck" coin - in this case, your bad luck (and the OP's good luck).

Stepping outside an array is bad news, regardless of whether it crashes or not.

I still fail to see why you posted C code in the C++ section?