a issue in thread programming

I have to create two threads. Then one thread will take input by using scanf function and then another thread will print the input value. How to do that. My following program is giving segmentation fault.

Code:

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#include<stdio.h>
#include<stdlib.h>
#include<pthread.h>
#include<unistd.h>
void *scan(void *s)
{
int *s1=(int *)s;
scanf("%d",s1);
pthread_exit((void *)s1);
}
void *print(void *s)
{
int *s1=(int *)s;
printf("%d",(*s1));
}
int main()
{
pthread_t tid1,tid2;
int *s;
pthread_create(&tid1,NULL,scan,NULL);
pthread_join(tid1,(void **)&s);
sleep(5);
pthread_create(&tid2,NULL,print,(void *)s);
pthread_join(tid2,NULL);
return 0;
}

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Well you pass a NULL pointer to scan, which you then dereference.

Code:

---

#include<stdio.h>
#include<stdlib.h>
#include<pthread.h>
#include<unistd.h>
void *scan(void *s)
{
    int *s1=malloc(sizeof(int));
    scanf("%d",s1);
    pthread_exit(s1);
}
void *print(void *s)
{
    int *s1=s;
    printf("%d",*s1);
    free(s1);
    return NULL;
}
int main()
{
    pthread_t tid1,tid2;
    void *temp;
    pthread_create(&tid1,NULL,scan,NULL);
    pthread_join(tid1,&temp);
    sleep(5);
    pthread_create(&tid2,NULL,print,temp);
    pthread_join(tid2,NULL);
    return 0;
}

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