Why do character arrays accept non ASCII characters in C++?

Question

So, I want to be able to use Chinese characters in my C++ program, and I need to use some type, to hold such characters beyond the ASCII range.

However, I tried to run the following code, and it worked.

    #include <iostream>

    int main() {
      char snet[4];
      snet[0] = '你';
      snet[1] = '爱';
      snet[2] = '我';
      std::cout << snet << std::endl;
      int conv = static_cast<int>(snet[0]);
      std::cout << conv << std::endl; // -96
    }

This doesn't make sense, as since a sizeof(char) in C++, for the g++ compiler evaluates to 1, yet Chinese characters cannot be expressed in a single byte.

Why are the Chinese characters here being allowed to be housed in a char type?

What type should be used to house Chinese characters or non-ASCII characters in C++?

Answer 1

When you compile the code using -Wall flag you will see warnings like:

warning: overflow in implicit constant conversion [-Woverflow] snet[2] = '我';

warning: multi-character character constant [-Wmultichar] snet1 = '爱';

Visual C++ in Debug mode, gives the following warning:

c:\users\you\temp.cpp(9): warning C4566: character represented by universal-character-name '\u4F60' cannot be represented in the current code page (1252)

What is happening under the curtains is that your two byte Chinese characters are implicitly converted to a char. That conversion overflows and therefore you are seeing a negative value or something weird when you print it in the console.

Why are the Chinese characters here being allowed to be housed in a char type?

You can, but you shouldn't, the same way that you can define char c = 1000000;

What type should be used to house Chinese characters or non-ASCII characters in C++?

If you want to store Chinese characters and you can use C++11, go for UTF-8 encoding with std::string (live example).

std::string msg = u8"你爱我";