/in/foo.cc: In function 'int main()':
/in/foo.cc:28:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while (start < reversed.length() - 1 && reversed[start] == '0') {
            ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
/in/foo.cc:54:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while (firstNonZero < minStr.length() && minStr[firstNonZero] == '0') {
            ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~
/in/foo.cc:57:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     if (firstNonZero < minStr.length()) {
         ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~