Compilare: main.cpp: In function 'int eval(std::__cxx11::string)': main.cpp:40:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<sir.size(); i++) ~^~~~~~~~~~~ main.cpp:49:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i < sir.size() && isdigit(sir[i])) ~~^~~~~~~~~~~~ main.cpp: In function 'int operatie(char, int, int)': main.cpp:32:1: warning: control reaches end of non-void function [-Wreturn-type] } ^