Re: Using std::lexicographical_compare with ignore case equality doesn't always work

The short snippet below demonstrates the problem I'm having with
std::lexicographical_compare() in that it does not reliably work!

#include <iostream>
#include <vector>
#include <ctype.h>

bool compare_ignore_case_equals(char c1, char c2)
{
        return toupper(c1) == toupper(c2);
}

bool compare_ignore_case_less(char c1, char c2)
{
        return toupper(c1) < toupper(c2);
}

int main(int argc, char *argv[])
{
        std::vector<std::string> args(argv + 1, argv + argc);
        const char *words[] =
        {
                "add", "del", "new", "help"
        };

        std::vector<std::string> list(words, words + (sizeof words / sizeof
        words[0]));
        std::vector<std::string>::iterator word = list.begin();
        while (word != list.end())
        {
                std::cout << "Testing " << *word << " = " << args[0];
                if (std::lexicographical_compare(
                        word->begin(), word->end(),
                        args[0].begin(), args[0].end(),
                        compare_ignore_case_equals))
                {
                        std::cout << " found!\n";
                        break;
                }

                std::cout << "\n";
                word++;
        }
}