Compilare: user.cpp: In function ‘int main()’: user.cpp:25:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("divk.in","r",stdin); ^ user.cpp:26:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("divk.out","w",stdout); ^ user.cpp:31:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d",&n,&k,&A,&B); ^ user.cpp:33:50: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for( i = 1; i <= n; ++i ) scanf("%lld",&v[i]); ^ user.cpp:64:22: warning: ‘f’ may be used uninitialized in this function [-Wmaybe-uninitialized] ans += f - ii; ^