Compilare: user.cpp: In member function ‘bigint& bigint::operator+=(const bigint&)’: user.cpp:15:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0, j = 0; i < v.size(); ++i){ ~~^~~~~~~~~~ user.cpp:16:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i < rhs.v.size()) ~~^~~~~~~~~~~~~~ user.cpp: In member function ‘bigint& bigint::operator*=(int)’: user.cpp:32:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v.size(); ++i){ ~~^~~~~~~~~~