Compilare: user.cpp: In function ‘bool e_palindrom(std::string)’: user.cpp:10:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < s.size()/2 ; i++) ^ user.cpp:11:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(s[i] != s.size()-1-i) return false; ^ user.cpp: In function ‘int solve()’: user.cpp:21:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0 ; i <= sir.size()-1 ; i++){ ^ user.cpp:23:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( j = i ; j <= sir.size()-1 ; j++) ^ user.cpp:32:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^