public IEnumerable <int> Select(IEnumerable <int> sequence, Func <int, bool> call_back_fun)
{
if (sequence == null)
{
throw new ArgumentException("sequence cann't be null");
}
BPlusTree TempTree = new BPlusTree();
foreach (int elem in sequence)
{
if (call_back_fun(elem))
{
TempTree.insert(elem);
}
}
return(TempTree.Get_all_data(1000));
}