Microsoft 9GD00001 manual Returning Data and Using Method Results

78Microsoft Visual Studio 2010: A Beginner’s Guide

VB:

Sub PrintCustomerReport(

ByVal customers As String(),

Optional ByVal title As String = "Customer Report")

Console.WriteLine(title)

Console.WriteLine()

For Each name In customers

Console.WriteLine(name)

Next

End Sub

The preceding code requires callers to pass an array of customers, but it does not require a title. When writing methods, optional parameters must be listed last. Here’s a method call without the optional parameter:

C#:

custProg.PrintCustomerReport(customerNames);

VB:

msgPrint.PrintCustomerReport(customerNames)

Because the caller didn’t pass an argument for title, the value of title inside of PrintCustomerReport becomes the default value assigned to the title parameter.

In addition to passing arguments to methods, you can receive values returned from methods.

Returning Data and Using Method Results

It is common to call methods that return values. To demonstrate the proper syntax, Listing 3-7 contains a method that accepts an int and returns the squared value of that int. Calling code then assigns the return value from the method to a variable and displays the value on the console window. Create a new class named Calc.cs or Calc. vb to hold the new method.

Listing 3-7 Returning values from methods

C# (Program.cs):

using System;

using System.Collections.Generic; using System.Linq;

using System.Text;