Comparing LPCWSTR in if()

Question

I feel like I am missing something very obvious here...

In my program, I read user input from an edit box using GetWindowText(),
followed by this code:

if (x == L"R" || x == L"C" || x == L"L"){ n = 1; }
else{ n = 9; }

The debugger clearly says that x is L"R", but n is getting set as 9.

Is using if() in this situation wrong and should I use something else?

Answer 1

x is a wchar* pointer. The debugger is smart enough to show you the data that x is pointing at. The actual data is elsewhere in memory.

L"R" and the other values are string literals. They are implemented as pointers to wchar_t[] arrays stored in your app's read-only data segment.

Your if statement is comparing pointers to pointers, which will fail if they are not pointing at the same memory (in this case, they do not). To compare the actual data being pointed at, you need to use lstrcmpW() or similar function, eg:

if ((lstrcmpW(x, L"R") == 0) ||
    (lstrcmpW(x, L"C") == 0) ||
    (lstrcmpW(x, L"L") == 0))
{
    n = 1;
}
else
{
    n = 9;
}