Deferred query execution

The query operators is that they execute not when constructed but when ecumerated (in other words, when MoveNext is called on its enumerator)

LINQ sample:

var numbers = new List();
numbers.Add(1);
var query = from n in numbers select n * 10;
numbers.Add(10);
foreach (int i in query)
{
Console.WriteLine(i);
}
Console.ReadLine();


The number 10 is added into the query result, this is called lazy evalution or deferred.
This feature seperate the query construction from query execution