Compilare: user.cpp: In member function ‘void BigNumber::operator+=(const BigNumber&)’: user.cpp:25:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] c[i] += t + (i < delta.size() ? delta[i] : 0); ^ user.cpp: In member function ‘BigNumber BigNumber::operator*(const BigNumber&)’: user.cpp:39:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < c.size(); ++i) { ^ user.cpp:40:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < delta.size(); ++j) { ^ user.cpp:47:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < result.size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:96:19: warning: format ‘%lld’ expects argument of type ‘long long int*’, but argument 2 has type ‘int*’ [-Wformat=] scanf("%lld", &n); ^ user.cpp:92:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("grazing.in", "r", stdin); ^ user.cpp:93:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("grazing.out", "w", stdout); ^ user.cpp:96:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld", &n); ^