Compilare: user.cpp: In function ‘bool cmp(std::string, std::string)’: user.cpp:14:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i<str2.size() && j<str1.size(); i++) ^ user.cpp:14:47: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i<str2.size() && j<str1.size(); i++) ^ user.cpp:17:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] return (j == str1.size()); ^ user.cpp: In function ‘int main()’: user.cpp:56:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < nr.size(); i++) ^