An example. This program declares and instantiates a char array in 3 ways. Usually in programs, the shortest syntax form is best, as it reduces the amount of text to read.
Version 1 Here the shortest syntax is used. The type of the array is only specified in the variable type.
Version 2 The array is allocated upon the managed heap and then each element is assigned in a separate statement.
Version 3 Here the New Char() syntax is used with an array initializer. This is also a short syntax form.
Module Module1
Sub Main()
' Version 1: use the initializer syntax.
Dim array1() As Char = {"a", "b", "c"}
' Version 2: use the long syntax.
Dim array2(2) As Char
array2(0) = "a"
array2(1) = "b"
array2(2) = "c"' Version 3: another syntax.
Dim array3() As Char = New Char() {"a", "c", "c"}
' Display lengths.
Console.WriteLine(array1.Length)
Console.WriteLine(array2.Length)
Console.WriteLine(array3.Length)
End Sub
End Module3
3
3
Example 2. With a char array, we can allocate the Char buffer all at once, and then assign into each element. We do not need to resize the buffer.
And The other approach you could use, which is slower, is the StringBuilder type and its Append function.
Module Module1
Sub Main()
' Allocate array of 100 characters.
Dim array(100) As Char
' Fill array with a character.
For index As Integer = 0 To 100
array(index) = "-"
Next
' Write some characters.
Console.WriteLine(array(0))
Console.WriteLine(array(100))
End Sub
End Module-
-
ToCharArray. The easiest way to get a char array is probably ToCharArray. We can specify a string literal, and create an array from the characters with this function in just one line.
Module Module1
Sub Main()
Dim value As String = "test"' Get char array from string.
Dim array() As Char = value.ToCharArray()
' Loop and print the chars.
For Each element As Char In array
Console.WriteLine("CHAR: {0}", element)
Next
End Sub
End ModuleCHAR: t
CHAR: e
CHAR: s
CHAR: t
Performance. How much faster is using a Char array to build up a sequence of characters in memory than is using a StringBuilder? This optimization can result in a 10X speedup.
A summary. A char array is the ideal array type for building up character data. It conforms to the standard array syntax in VB.NET. It can help many programs.
Dot Net Perls is a collection of pages with code examples, which are updated to stay current. Programming is an art, and it can be learned from examples.
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