c++ - Different between the two initialization of char pointers

Question

    #include <iostream>
using namespace std;

int main() {
    char* s = 0;
    char *t = "";
    cout<<s<<endl;
    cout<<t<<endl;
    return 0;
}

Hey, the output for the above code is empty. Could someone please explain the difference between the two (0 and "")?

question from:https://stackoverflow.com/questions/65870885/different-between-the-two-initialization-of-char-pointers

Answer 1

char* s = 0;

Initializing a char pointer that points to null.

char *t = "";

Initializing a char pointer with a string literal, it's practically empty as is a null character used to terminate C-style strings, what you have done is effectively equivalent to std::string t = "";. The following code:

char *t = "hello";
cout << t << endl;

...would have resulted in:

hello

I have to point out that you invoked undefined behavior by passing a null pointer to cout, your program most likely crashed after cout<<s<<endl;