Compilare: user.cpp: In function ‘std::vector<int> add(std::vector<int>, std::vector<int>)’: user.cpp:21:50: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < b.size() - a.size() + 1; ++i) ^ user.cpp:25:54: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < a.size() - b.size() + 1; ++i) ^ user.cpp: In function ‘int main()’: user.cpp:66:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < a[1].size(); ++i) ^ user.cpp:52:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("petrecere.in", "r", stdin); ^ user.cpp:53:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("petrecere.out", "w", stdout); ^ user.cpp:54:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] int n; scanf("%d", &n); ^