Compilare: user.cpp: In function ‘int main()’: user.cpp:14:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cover.in","r",stdin); ^ user.cpp:15:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cover.out","w",stdout); ^ user.cpp:16:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&n,&l); ^ user.cpp:18:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&cost[i]); ^ user.cpp:21:68: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] segbegin[v[i].second]=max(segbegin[v[i].second],v[i].first); ^