Compilare: user.cpp: In member function ‘BigInt BigInt::operator+(BigInt)’: user.cpp:31:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v.size(); i++) ^ user.cpp: In member function ‘BigInt BigInt::operator-(BigInt)’: user.cpp:47:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v.size(); i++) ^ user.cpp: In member function ‘BigInt BigInt::operator*(int)’: user.cpp:64:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v.size(); i++) ^ user.cpp: In member function ‘std::string BigInt::str()’: user.cpp:113:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] ret += (i < v.size()-1 ? std::string(basewidth-s.size(), '0') : "") + s; ^ user.cpp: In function ‘BigInt operator*(int, BigInt)’: user.cpp:124:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < b.v.size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:142:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("rute.in", "r", stdin); ^ user.cpp:143:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("rute.out", "w", stdout); ^ user.cpp:145:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^