Compilare: user.cpp: In function ‘std::vector<int> multiply(std::vector<int>&, std::vector<int>&)’: user.cpp:34:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i<A.size()) { ^ user.cpp:37:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i<B.size()) { ^ user.cpp:48:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<ans.size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:70:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(a.size() <= x) a.push_back(0); ^ user.cpp:77:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(b.size() <= x) b.push_back(0); ^ user.cpp:81:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<c.size(); i++) { ^ user.cpp:59:9: warning: unused variable ‘x’ [-Wunused-variable] int n, x; ^ user.cpp:55:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bacterii2.in","r",stdin); ^ user.cpp:56:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bacterii2.out","w",stdout); ^