I have string input. I want to check all the characters and prompt the user if there is any Unicode character in input string.
How can I do this validation in C++.
eg. In Notepad if you enter any Unicode character and try to save it with ANSI Encoding, it will prompt about Unicode character. I want to do similar validation.
You can use IsTextUnicode function. That's the function notepad uses as far as I know.
MSDN-Link: http://msdn.microsoft.com/en-us/library/windows/desktop/dd318672%28v=vs.85%29.aspx
Just insert NULL as the last parameter.
#include <string> #include <Windows.h> int main() { std::string s = "Hallo!"; std::wstring ws = L"Hello!"; if (::IsTextUnicode(ws.c_str(), ws.length(), NULL) == 1) { // is unicode int i = 0; } else { // no unicode int i = 1; } return 0; } 
What Notepad warns you about is slightly different: It warns you about Unicode characters that cannot be converted to the desired code page. IOW, WideCharToMultiByte(CP_ACP, ..., &lpUsedDefaultChar) causes lpUsedDefaultChar to be set to TRUE.
Substitute CP_ACP for the encoding you want, except CP_UTF8 which makes no sense. UTF8 supports all Unicode characters.
An easy way is to allow Unicode and store the text as UTF-8. As UTF-8 is a superset of ASCII it's very easy to find characters which are not ASCII (they have the high bit set).
