c++ - What makes this usage of pointers unpredictable?

Question

I'm currently learning pointers and my professor provided this piece of code as an example:

//We cannot predict the behavior of this program!

#include <iostream>
using namespace std;

int main()
{
    char * s = "My String";
    char s2[] = {'a', 'b', 'c', ''};

    cout << s2 << endl;

    return 0;
}

He wrote in the comments that we can't predict the behavior of the program. What exactly makes it unpredictable though? I see nothing wrong with it.

Answer 1

The behaviour of the program is non-existent, because it is ill-formed.

char* s = "My String";

This is illegal. Prior to 2011, it had been deprecated for 12 years.

The correct line is:

const char* s = "My String";

Other than that, the program is fine. Your professor should drink less whiskey!