Compilare: user.cpp: In function ‘int main()’: user.cpp:6:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] {freopen("cool.in","r",stdin); ^ user.cpp:7:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cool.out","w",stdout); ^ user.cpp:8:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d",&v,&n,&k); ^ user.cpp:9:35: 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",&a[i]); ^