c++ dangerous pointers practice? [duplicate]

Question

#include <stdio.h>


int *pPointer;

void SomeFunction()
{
    int nNumber;
    nNumber = 25;    

    // make pPointer point to nNumber:

    pPointer = &nNumber;
}

void main()
{
    SomeFunction(); // make pPointer point to something

    cout<< "Value of *pPointer: "<< *pPointer <<endl;
}

I have been told that using pointers like this is dangerous, could anyone please explain why it is dangerous and what would be the 'safe' way to write that piece of code? will 25 always be printed out to the screen in that way? if not then why?

Answer 1

Using a pointer to local variable outside of the scope of the variable is always dangerous. It invokes undefined behavior.