Function for getting the ordinal of a number?

I was about to write a C++ function doing the following:

1 ---> "1st"
2 ---> "1nd"
3 ---> "3rd"
...
17657 --> "17657th"
...

i.e. produces the ordinal extension string for that number (it doesn't have to do an itoa() of the number itself). But then I thought "surely something in the standard library or boost does this already?"

Notes:

• I know it's not hard to write this, there's an implementation in Python right here on SO, I just don't want to duplicate code.
• I need this in English, obviously. A multi-language version would be nice for political-correctness considerations, not more than that...

Here's what I ended up writing:

const char* ordinal_suffix(int n)
{
    static const char suffixes [][3] = {"th", "st", "nd", "rd"};
    int ord = n % 100;
    if (ord / 10 == 1) { ord = 0; } // 11th ... 19th
    ord = ord % 10;
    if (ord > 3) { ord = 0; }
    return suffixes[ord];
}

The code golf solutions are cute, but - they really do optimize for terseness, not anything else. This is faster (although it could perhaps be made even faster by putting the suffixes in a .cpp out of the function body and making the code inlinable), much clearer, and still more terse than most other answers here.

Notes:

• This code is actually valid C89 code, not just valid C++ code. :-)
• You may want to rename this function for terseness in use. I sometimes call it xth() or even just th().
• You can templatize this over the integer input type; or use long long int and implicit conversion.
• The code doesn't assume n is negative, but it's not obvious what the ordinal suffix should be for negative numbers; and the result for negative n's will probably not be what you would expect.