Compilare: main.cpp: In function 'int getNumber(int&, const string&)': main.cpp:40:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(index < s.size() && '0' <= s[index] && s[index] <= '9') { ~~~~~~^~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:59:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(index < s.size()) { ~~~~~~^~~~~~~~~~ main.cpp: In function 'int getResult(int, int, char)': main.cpp:24:1: warning: control reaches end of non-void function [-Wreturn-type] } ^