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// Iterator method.

public IEnumerator GetEnumerator()

{

foreach (Car c in carArray)

{

yield return c;

}

}

}

Notice that this implementation of GetEnumerator() iterates over the subitems using internal

foreach logic and returns each Car to the caller using the yield return syntax. The yield keyword is

used to specify the value (or values) to be returned to the caller’s foreach construct. When the yield

return statement is reached, the current location is stored, and execution is restarted from this

location the next time the iterator is called.

Iterator methods are not required to make use of the foreach keyword to return its contents.

It is also permissible to define this iterator method as follows:

public IEnumerator GetEnumerator()

{

yield return carArray[0];

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yield return carArray[1];

yield return carArray[2];

yield return carArray[3];

}

In this implementation, notice that the GetEnumerator() method is explicitly returning a new

value to the caller with each pass through. Doing so for this example makes little sense, given that if

we were to add more objects to the carArray member variable, our GetEnumerator() method would

now be out of sync. Nevertheless, this syntax can be useful when you wish to return local data from

a method for processing by the foreach syntax.