Visual Basic.NET How to Program (PDF)

Chapter 15 Strings, Characters and Regular Expressions 637
access an element outside the bounds of the character array, an ArgumentOutOfRangeException
is thrown.
Line 23 assigns to string4 a new String object, using the String constructor
that takes as arguments a character and an Integer specifying the number of times to
repeat that character in the String.
Each instance of variable quotes (lines 25–28) represents a double quote character
("). Visual Studio .NET treats double quotes as delimiters for Strings and does not treat
them as part of a String. We can represent a quotation mark within a String by using
the numerical code of the character (e.g., line 11) or by placing consecutive double quote
characters ("") in the String.
15.4 String Length and Chars Properties, and CopyTo
Method
The application in Fig. 15.2 presents the String property Chars, which facilitates the
retrieval of any character in the String, and the String property Length, which returns
the length of the String. The String method CopyTo copies a specified number
of characters from a String into a Char array.
1 ' Fig. 15.2: StringMiscellaneous.vb
2 ' Using properties Length and Chars, and method CopyTo
3 ' of class string.
4
5 Imports System.Windows.Forms
6
7 Module modMiscellaneous
8
9 Sub Main()
10 Dim string1, output As String
11 Dim characterArray As Char()
12 Dim i As Integer
13 Dim quotes As Char = ChrW(34)
14
15 string1 = "hello there"
16 characterArray = New Char(5) {}
17
18 ' output string
19 output = "string1: " & quotes & string1 & quotes
20
21 ' test Length property
22 output &= vbCrLf & "Length of string1: " & string1.Length
23
24 ' loop through characters in string1 and display
25 ' reversed
26 output &= vbCrLf & "The string reversed is: "
27
28 For i = string1.Length - 1 To 0 Step -1
29 output &= string1.Chars(i)
30 Next
Fig. 15.2 String Length and Chars properties, and CopyTo method (part 1
of 2).