Why does this not work?

Question

im trying to create the string library and ive ran across a problem.
i cant get the operator [] to work. what im trying to this is this:
example with string:
string test ="test";
test[2]= 'm';
my functions are:
the header file is:
char& operator[](int loc);
the cpp file is:

char& str::operator[](int loc) {
return str_real[loc];
}

Answer 1

Tomer Sim below is what default behavior of [] operator for string in c++:

string s = "Test";
s[2] = 'M';

cout << s; // prints TeMt

I got your point that you are trying to overload [] operator for string... correct me if my understanding is wrong.

Now what I don't understand is your expected output.. what you want as output is not clearer to me with overloaded operator