Compilare: main.cpp: In member function 'BigInt BigInt::operator+(BigInt)': main.cpp:26:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v.size(); i++) ~~^~~~~~~~~~ main.cpp: In member function 'BigInt BigInt::operator-(BigInt)': main.cpp:42:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v.size(); i++) ~~^~~~~~~~~~ main.cpp: In member function 'BigInt BigInt::operator*(int)': main.cpp:59:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v.size(); i++) ~~^~~~~~~~~~ main.cpp: In member function 'std::__cxx11::string BigInt::str()': main.cpp:108:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] ret += (i < v.size()-1 ? std::string(basewidth-s.size(), '0') : "") + s; ~~^~~~~~~~~~~~ main.cpp: In function 'BigInt operator*(int, BigInt)': main.cpp:119:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < b.v.size(); i++) ~~^~~~~~~~~~~~