C# 4 and .NET 4

146 ❘ ChaPTer 6 ArrAys And tuples
}
}
}
yield break;
yield return cross;
code snippet YieldDemo/GameMoves.cs
From the client program, you can use the class GameMoves as follows. The first move is set by setting
enumerator to the enumerator type returned by game.Cross(). In a while loop, enumerator.MoveNext()
is called. The first time this is invoked, the Cross() method is called, which returns the other enumerator
with a yield statement. The returned value can be accessed with the Current property and is set to the
enumerator variable for the next loop:
var game = new GameMoves();
IEnumerator enumerator = game.Cross();
while (enumerator.MoveNext())
{
enumerator = enumerator.Current as IEnumerator;
}
The outcome of this program shows alternating moves until the last move:
Cross, move 0
Circle, move 1
Cross, move 2
Circle, move 3
Cross, move 4
Circle, move 5
Cross, move 6
Circle, move 7
Cross, move 8
code snippet YieldDemo/Program.cs
TuPles
Arrays combine objects of the same type; tuples can combine objects of different types. Tuples have the
origin in functional programming languages such as F# where they are used often. With .NET 4, tuples are
available with the .NET Framework for all .NET languages.
.NET 4 defines eight generic Tuple classes and one static Tuple class that act as a factory of tuples. The
different generic Tuple classes are here for supporting a different number of elements; e.g., Tuple
contains one element, Tuple contains two elements, and so on.
The method Divide() demonstrates returning a tuple with two members — Tuple. The
parameters of the generic class define the types of the members, which are both integers. The tuple is created
with the static Create() method of the static Tuple class. Again, the generic parameters of the Create()
method define the type of tuple that is instantiated. The newly created tuple is initialized with the result
and reminder variables to return the result of the division:
public static Tuple Divide(int dividend, int divisor)
{
int result = dividend / divisor;
int reminder = dividend % divisor;
}
return Tuple.Create(result, reminder);
code snippet TuplesSample/Program.cs
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