Compilare: user.cpp: In function ‘int main()’: user.cpp:58:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("gutui.in","r",stdin); ^ user.cpp:59:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("gutui.out","w",stdout); ^ user.cpp:60:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&n,&height,&u); ^ user.cpp:61:55: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (i=1; i<=n; ++i) scanf("%d%d",&a[i].r,&a[i].l); ^