trim a string of a set of characters

strim.cc

const char white[] = " \t\r";

string trim(string& str)
{
    if(str.length() ==0) { return str;}
    size_t first = str.find_first_not_of(white);
    if(first == string::npos) return "";
    size_t last = str.find_last_not_of(white);
    return str.substr(first, (last-first+1));
}

Note that it trims the left and right extremities of a string, not the whole string itself.