Padding stl strings in C++

Question

I\'m using std::string and need to left pad them to a given width. What is the recommended way to do this in C++?

Sample input:

123
         


        

Answer 1

Create a new string of 10 spaces, and work backwards in both string.

string padstring(const string &source, size_t totalLength, char padChar)
{
    if (source.length() >= totalLength) 
        return source;

    string padded(totalLength, padChar);
    string::const_reverse_iterator iSource = source.rbegin();
    string::reverse_iterator iPadded = padded.rbegin();
    for (;iSource != source.rend(); ++iSource, ++iPadded)
        *iPadded = *iSource;
    return padded;
}