bool permutate(char *str)
{
    int len = strlen(str);
    for(bool stop = false; !stop;) {
        dump << str << endl;
        for(int i = len - 2, j = len - 1;;j=i--) {
            if(str[i] < str[j]) {
                int k = len - 1;
                while(str[k] <= str[i])
                    --k;
                swap(str[i], str[k]);
                reverse(str + j, str + len);
                break;
            } else if(i <= 0) {
                stop = true;
                break;
            }
        }
    }
}

int main()
{
    char chars[] = "abcd";
    permutate(chars);
    return 0;
}