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Object-oriented Programming in C#
Collection Classes
Iterator blocks and yield return

Iterators are implemented by methods made with iterator blocks

IEnumerator<Type> Method() { // iterator block
  Type t;

  yield return t;

A method formed by an iterator block.

  • Characteristics

    • The return type of the method must be an enumerator or an enumerable

    • A method with an iterator block is not executed immediately when calling it

    • Instead an enumerable object is created and returned

    • Execution starts when MoveNext is activated on the enumerable object

The compiler transforms a method with an iterator block to an underlying state machine which manages the traversal

Go to exerciseInfinite Collections of Integers