read txt file in c++ (chinese)

Question

I'm trying to develop function that check whether chinese word which user enters is in the txt file or not. The following is the code. But it is not working. I want to know what the problem is. Help me please.

setlocale(LC_ALL, "Chinese-simplified");
locale::global(locale("Chinese_China"));
SetConsoleOutputCP(936);
SetConsoleCP(936);

bool exist = FALSE;

cout << "\n\n <Find the keyword whether it is in that image or not> \n ";
cout << "Enter word to search for: ";
wstring search;
wcin >> search; //There is a problem to enter chinese.

wfstream file_text("./a.txt");
wstring line;
wstring::size_type pos;

while (getline(file_text, line))
{
    pos = line.find(search);
    if (pos != wstring::npos) // string::npos is returned if string is not found
    {
        cout << "Found!" << endl;
        exist = true;
        break;
    }
}

when I use this code, The result is as follows.

const int oldMbcp = _getmbcp();
_setmbcp(936);
const std::locale locale("Chinese_China.936");
_setmbcp(oldMbcp);

Answer 1

If you're interested in more details, please see stod-does-not-work-correctly-with-boostlocale for a more detailed description of how locale works,

In a nutshell the more interesting part for you:

1. std::stream (stringstream, fstream, cin, cout) has an inner locale-object, which matches the value of the global C++ locale at the moment of the creation of the stream object. As std::in is created long before your code in main is called, it has most probably the classical C locale, no matter what you do afterwards.
2. you can make sure, that a std::stream object has the desirable locale by invoking std::stream::imbue(std::locale(your_favorit_locale)).

I would like to add the following:

1. It is almost never a good idea to set the global locale - it might break other parts of the program or third part libraries - you never know.

2. std::setlocale and locale::global do slightly different things, but locale::global resets not only the global c++-locale but also the c-locale (which is also set by std::setlocale, not to be confused with the classical "C" locale), so you should call it in another order if you want to have c++ locale set to Chinese_China and C locale to chinese-simplified

First locale::global(locale("Chinese_China"));

And than setlocale(LC_ALL, "Chinese-simplified");

Answer 2

If using Vladislav's answer does not solve this, take a look at answer to stl - Shift-JIS decoding fails using wifstrem in Visual C++ 2013 - Stack Overflow:

const int oldMbcp = _getmbcp();
_setmbcp(936);
const std::locale locale("Chinese_China.936");
_setmbcp(oldMbcp);

There appears to be a bug in Visual Studio's implementation of locales. See also c++ - double byte character sequence conversion issue in Visual Studio 2015 - Stack Overflow.

Answer 3

Try locale::global(locale("Chinese_China.936")); or locale::global(locale("")); And for LC_ALL "chinese-simplified" or "chs"