Compilare: main.cpp: In function 'std::pair<int, double> solve(std::__cxx11::string)': main.cpp:15:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s.size();i++) ~^~~~~~~~~ main.cpp:26:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(++i<s.size() && isdigit(s[i])) ~~~^~~~~~~~~ main.cpp:29:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i<s.size() && s[i]=='x') *cfx+=nr,i++; ~^~~~~~~~~ main.cpp:42:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^