Topic 5.3.3: Iterative Constructs
FOR....NEXT
- It repeats a group of statements a specified number of times and a loop index counts the number of loop iterations as the loop executes.
Syntax:
For counter [ As datatype ] = start To end [ Step step ]
[ statements ]
Next [ counter ]
Example:
Dim a As Byte
For a = 10 To 20
' Statement to print
Console.WriteLine("value of a: {0}", a)
Next
WHILE LOOP
- It executes a series of statements as long as a given condition is True.
Syntax:
While condition
[ statements ]
End While
- Here, statement(s) may be a single statement or a block of statements. The condition may be any expression, and true is logical true. The loop iterates while the condition is true.
- When the condition becomes false, program control passes to the line immediately following the loop.
- Here, key point of the While loop is that the loop might not ever run. When the condition is tested and the result is false, the loop body will be skipped and the first statement after the while loop will be executed.
Example:
Dim a As Integer = 10
While a < 20
Console.WriteLine("value of a: {0}", a)
a = a + 1
End While
FOR EACH LOOP
- It repeats a group of statements for each element in a collection. This loop is used for accessing and manipulating all elements in an array or a VB.Net collection.
Syntax:
For Each element [ As datatype ] In group
[ statements ]
Next [ element ]
Example:
Dim anArray() As Integer = {1, 3, 5, 7, 9}
Dim arrayItem As Integer
For Each arrayItem In anArray
Console.WriteLine(arrayItem)
Next
Last modified: Wednesday, 1 April 2020, 3:44 PM