Why ptr not becomes Dangling pointer because when return pointer who store the address of local variable get destroy after return function?

Question

#include<stdio.h>
 
int *func(int * ptr){
    int a = 12;
    int *c = &a;
    return c; // here it returns the pointer by storing the address of local variable   
}

int main()
{
    int *ptr = NULL;
    ptr= func(ptr); // here the address is stored but the local variable gets destroyed
    printf("the value is %d\n",*ptr); // So how can it print the value 12 here if local variable gets destroyed or did I miss something?    
    return 0;
}

Output

The valus is 12

But how it is possible because when it returns the address by storing it in the pointer the variable get destroy so ptr becomes dangle but it still gives output 12.

Answer 1

Because nothing actually enforces that the memory location your previous stack frame was in gets overwritten or destroyed. The memory where your pointer was declared still belongs to your application, and is probably sitting there untouched.

What you've invoked here is undefined behavior which may do unpredictable things, including work when it's not "supposed" to.