Compilare: user.cpp: In function ‘int main()’: user.cpp:19:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < strlen( s ); i++){ ^ user.cpp:28:47: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < v.size(); j++) ^ user.cpp:35:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < v.size(); j++) ^