Compilare: user.cpp: In function ‘std::string ans1(std::string)’: user.cpp:11:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < t.size(); i++) { ^ user.cpp: In function ‘std::string ans2(std::string)’: user.cpp:25:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < t.size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:62:17: warning: ‘c’ may be used uninitialized in this function [-Wmaybe-uninitialized] out << c; ^