Compilare: user.cpp: In function ‘int main()’: user.cpp:18:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < s.size(); i++) ~~^~~~~~~~~~ user.cpp:26:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i <= s.size(); i++) ~~^~~~~~~~~~~ user.cpp:28:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(pos = 0; pos < s.size(); pos++) ~~~~^~~~~~~~~~ user.cpp:41:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < upd[pos].size(); i++) ~~^~~~~~~~~~~~~~~~~