Value pointed by array-name in 2-D array

Question

#include <iostream>
using namespace std;

int main() {
    char a[][6] = { "hello", "hii" };
    cout << a << ", " << *a << ", " << **a;
    return 0;
}

OUTPUT : 0x7ffd1f44a20c, hello, h

Now, as we know that the array-name(in this case 'a') in case of 2D array points to the 1D array (in this case "hello"), *a will point to the element in that (1D array pointed by a) array and **a will give use the value pointed by *a. Now in this case i am little confused because of two reasoning:

1. The output is right, since the value pointed by 'a' is "hello", and *a will print the value pointed by 'a'.
2. The output is wrong, since *a itself is pointing the element inside 1D array and hence *a should have printed the address corresponding to the first element of 1D array pointed by a and the output should have been :

Expected output : 0x7ffd1f44a20c, address of h, h

Thank you very much for patience!

Answer 1

a is only a "2D array" in a limited sense. This is part of the somewhat-weird and not-super-consistent array semantics C++ inherits from C, like array-to-pointer decay.

So, when you define a, what gets placed in memory is: h, e, l, l, o, \0, h, i, i, \0, \0, \0 - in sequence.

• When you type a[x][y], that's the x*6 + y'th character in that sequence (type char);
• When you type a[x], that decays into a char* pointing to the x*6'th character in the sequence.
• When you type a, that decays into a pointer to 6-element arrays, pointing to a 6-element array starting at the 0'th position in the sequence.

See this also on GodBolt (using the type_name facility).