Compilare: user.cpp: In function ‘int string_to_int(const string&)’: user.cpp:12:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<x.size();i++) { ^ user.cpp: In function ‘int main()’: user.cpp:60:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<parsed.size();i++) ^