Compilare: user.cpp: In function ‘int main()’: user.cpp:59:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<D.size();i++) a.push_back(D[i]); ^ user.cpp:63:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<a.size();i++){ ^ user.cpp:43:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("vase.in","r",stdin); ^ user.cpp:44:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("vase.out","w",stdout); ^ user.cpp:46:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld\n",&n); ^ user.cpp:48:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld %c",&x,&op); ^ user.cpp:56:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld",&targ); ^