Error C2196: case value '?' already used

Question

Ok, curious error while building with Visual Studio Ultimate 2012 (probably issue with ANSI, unicode etc) in the code...

switch (input[index])
{
    case 'א': // Alef Hebrew character
        if (/*conditional*/) 
        {
            // Do stuff.
        }
    break;

    case 'ב': // Beth Hebrew character
        if (/*conditional*/)
        {
            //Do stuff
        }
    break;

    default:
    {
            //Do some other stuff.
    }
    break;

}

The second case parameter generates...

Error C2196: case value '?' already used

Simple fix if possible.

Answer 1

Assuming input is an array of wchar_ts, your problem is that you're comparing a wide character to a narrow character literal.

As PeterT said in the comments:

If you save the file as utf-8 encoded then א is 0xD790 and ב is 0xD791, so if input[index] is of type char both would try to match 0xD7.

That's why you're getting the error you mentioned. (char has enough space to store an ASCII value, and the rest is omitted)

---

You can fix this by prefixing your literals with a capital L (turning them in to wide characters).

case L'א': // Alef Hebrew character
    if (/*conditional*/) 
    {
        // Do stuff.
    }
break;

case L'ב': // Beth Hebrew character
    if (/*conditional*/)
    {
        //Do stuff
    }
break;

---

Also, you need to make sure your source file is saved with unicode encoding & your compiler knows how to work with that.

Alternatively, you can simply escape the unicode value like so:

case L'\u05D0': // Aleph Hebrew character
// ...
case L'\u05D1': // Beth Hebrew character