Make a condition on const wchar_t*

Question

how can i make a condition with const wchar_t*?I have tried const wchar_t* password if (L"xyz" == password) {...} but it's not working

thank you

http://en.cppreference.com/w/cpp/string/wide/wcscmp or use `std::wstring`. — DeiDei, Jan 10 '17 at 11:17
@A.Adil So, do that? For future reference, "not working" is not useful problem description. — Algirdas Preidžius, Jan 10 '17 at 12:06
As stated above, your code just compares the addresses of the variables, so your if (L"xyz" == password) will always fail. If you want to see if the text is equal, you need to use wcscmp(L"xyz", password). — Willy K., Jan 10 '17 at 13:04

score 2 · Accepted Answer · answered Jan 10 '17 at 13:57

2

You should take a look at wcscmp

const wchar_t* password = L"xyz";
if (wcscmp(password, L"xyz") == 0) {
    // Strings are identical
}

answered Jan 10 '17 at 13:57

MPala

36
4

score 0 · Answer 2 · answered Jan 10 '17 at 14:58

When you are doing L"xyz" == whatever (or even the non-wide version, "xyz" == whatever) you are comparing pointers, not string contents.

E.g. say your variable password is stored at location 0x00100000 in memory, and the constant L"xyz" is stored at location 0x00200000. When you perform the equality test with the line L"xyz" == password what it is actually comparing is 0x00100000 == 0x00200000, which is obviously never going to be true.

What you need to do is use the library function wcscmp to compare wide-character strings. However, since this is tagged as C++, you should be using std::wstring and the overloaded operator == unless you have a reason to be using C strings. That may be where you're confused: when using std::string or std::wstring you can use == to compare strings because those classes overload the == operator so this code works just fine:

#include <iostream>
#include <string> 

int main(int argc, char *argv[])
{
    std::wstring wstr = L"Hello World";
    if(wstr == L"Hello World")
    {
        std::wcout << wstr << std::endl;
    }
    return 0;
}

As a side note, you really shouldn't be using constants to store passwords in your program unless they're encrypted somehow.

Make a condition on const wchar_t*

2 Answers2