Compilare: user.cpp: In function ‘int parc(std::string, std::string)’: user.cpp:10:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s1.size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:31:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<s1.size();i++) ^