Compilare: main.cpp: In function 'int trans(std::__cxx11::string)': main.cpp:40:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < s.size(); i++) ~~^~~~~~~~~~ main.cpp: In function 'int det_val_expresie_poloneza(std::vector<std::__cxx11::basic_string<char> >)': main.cpp:54:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < expol.size(); i++) ~~^~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:163:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < strlen(s); i++) ~~^~~~~~~~~~~ main.cpp:198:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i < strlen(s) && (s[i] >= '0' && s[i] <= '9')) ~~^~~~~~~~~~~