Compilare: user.cpp: In function ‘int main()’: user.cpp:32:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<v.size(); ++i){ ^ user.cpp:37:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<v.size(); ++i) ^ user.cpp:19:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("heavymetal.in","r",stdin); ^ user.cpp:20:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("heavymetal.out","w",stdout); ^ user.cpp:23:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:26:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&tmp.a,&tmp.b); ^