Passing array by reference in C++

Question

this might sound a very basic question, however i am having little confusing understanding this piece of code:

so i have a function that takes argument: const char * str1
Now that argument passed is defined as: const char (&str1)[5]

I would appreciate if you could elaborate a little how the character pointer array is defined in 2nd line?

EDIT:

template<unsigned N, unsigned M>
int compare(const char (&p1)[N], const char (&p2)[M]){
   return strcmp(p1,p2);
}

I am trying to understand how the non type parameter which is essentially translating to character string is defined here

Answer 1

Nothing is "essentially translating". The function template expects to be called with two array arguments.

char s[] = { 'a', 0, 'c' };

compare(s, "xyz");    //  first argument "s" is a named array, N = 3
                      //  second argument is a string literal, M = 4

You can use the same pattern for any array, but the special benefit for char-like arrays is that you can have literal arrays in the form of string literals.