Align text to center in string C++

Question

I have been trying to make a function in C++ for a gameserver DLL which aligns given text to center before returning the new string to Lua for processing. I have spent quite

Answer 1

Here's another way that will ensure the text is centered within a given width and is padded left and right with spaces.

std::string center(const std::string s, const int w) {
    std::stringstream ss, spaces;
    int pad = w - s.size();                  // count excess room to pad
    for(int i=0; i<pad/2; ++i)
        spaces << " ";
    ss << spaces.str() << s << spaces.str(); // format with padding
    if(pad>0 && pad%2!=0)                    // if pad odd #, add 1 more space
        ss << " ";
    return ss.str();
}

This could be written more elgantly or concisely.

Answer 2

std::string center (const std::string& s, unsigned width)
{
    assert (width > 0);
    if (int padding = width - s.size (), pad = padding >> 1; pad > 0)
        return std::string (padding, ' ').insert (pad, s);
    return s;
}

Answer 3

I'm going to assume you already know how to pass a string from Lua to C++ and return the result from C++ to Lua, so the only part we need to deal with is producing the centered string.

That, however, is pretty easy:

std::string center(std::string input, int width = 113) { 
    return std::string((width - input.length()) / 2, ' ') + input;
}