Stephens' C# Programming with Visual Studio® 2010 24-Hour Trainer

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LESSON 20 Reusing Code with Methods

The method takes two parameters, player1 and player2, that are passed by reference. The method

performs some complex calculations not shown here to assign the variables

player1 and player2.

It then returns

true to indicate that it found a match.

The following code shows how a program might call this method:

string playerA = null, playerB = null;

if (GetMatchup(ref playerA, ref playerB))

{

// Announce this match.

...

}

else

{

// No match is possible. We’re done.

...

}

This code declares variables playerA and playerB to hold the selected players’ names. It calls the

method, passing it the two player name variables preceded with the

ref keyword. Depending on

whether the method returns

true or false, the program announces the match or does whatever it

should when all of the matches have been played.

The

out keyword works similarly to the ref keyword except it doesn’t require that the input

variables be initialized. For example, in the preceding example if you don’t initialize

playerA

and

playerB to some value, Visual Studio will warn you that the variables are not initialized and

won’t let you run the program.

In contrast, if you use the

out keyword instead of ref, the values are assumed to be output

parameters from the method, and you are not required to initialize them.

If you use the

out keyword for a parameter, be sure that the method does not tr ...