不了解指针

Question

I have following C program.

#include <stdio.h>
int main()
{
    int *p, *q;
    *p=5;
    *q=6;
    printf("%d %d", *p, *q);
    return 0;
}

The code is not running. Whats wrong with this code??

Answer 1

Your pointer are not initialized, they need to point to valid memory using malloc or by taking address of a local variable.

#include <stdio.h>
int main()
{
    int p, q;
    int *pp = &p;
    int *pq = &q;
    *pp=5;
    *pq=6;
    printf("%d %d", *pp, *pq);
    return 0;
}

would work.