Handling Non-ASCII User Input

Handling non-ASCII user input in C++ requires careful consideration of character encodings and the use of appropriate data types. Here's a guide on how to approach this:

Use Wide Character Types

When dealing with non-ASCII input, it's often easier to use wide character types like wchar_t or char16_t. These can represent a wider range of characters than the basic char type.

1#include <iostream>
2#include <string>
3
4int main() {
5  std::wstring input;
6  std::wcout << L"Enter some text "
7    L"(including non-ASCII characters): ";
8  std::getline(std::wcin, input);
9  std::wcout
10    << L"You entered: " << input << L'\n';
11}

1Enter some text (including non-ASCII characters): 123 ❤️
2You entered: 123 ❤️

Set the Locale

To properly handle non-ASCII input and output, you may need to set the appropriate locale:

1#include <iostream>
2#include <string>
3#include <locale>
4
5int main() {
6  std::locale::global(std::locale(""));
7  std::wcout.imbue(std::locale());
8  std::wcin.imbue(std::locale());
9
10  std::wstring input;
11  std::wcout << L"Enter some text (including "
12                L"non-ASCII characters): ";
13  std::getline(std::wcin, input);
14  std::wcout << L"You entered: " << input;
15}

1Enter some text (including non-ASCII characters): 123 ❤️
2You entered: 123 ❤️

Use UTF-8 Encoding

If you prefer to work with UTF-8 encoding (which is becoming increasingly common), you can use the regular std::string type, but you need to ensure your environment is set up correctly:

1#ifdef _WIN32
2  #include <windows.h>
3#endif
4
5#include <iostream>
6#include <string>
7
8int main() {
9#ifdef _WIN32
10  SetConsoleOutputCP(CP_UTF8);
11  SetConsoleCP(CP_UTF8);
12#endif
13
14  std::string input;
15  std::cout << "Enter some text (including  "
16               "non-ASCII characters): ";
17  std::getline(std::cin, input);
18  std::cout << "You entered: " << input << '\n';
19}

1Enter some text (including non-ASCII characters): 123 ❤️
2You entered: 123 ❤️

Remember, when working with non-ASCII input, it's crucial to be consistent with your encoding throughout your program. Mixing different encodings can lead to unexpected results and display issues.

Also, be aware that the behavior of these examples may vary depending on your operating system, compiler, and terminal settings. Always test your program with a variety of inputs to ensure it handles non-ASCII characters correctly.