Lesson 9: Looping

Visual Basic allows a procedure to be repeated as many times as long as the processor could support. This is generally called looping .

9.1 Do Loop
The format are

a) Do While condition

Block of one or more VB statements

Loop

b) Do
Block of one or more VB statements
Loop While condition

c) Do Until condition
Block of one or more VB statements
Loop

d) Do
Block of one or more VB statements

Loop Until condition

Example 9.1

Do while counter <=1000

num.Text=counter

counter =counter+1

Loop

* The above example will keep on adding until counter >1000.

The above example can be rewritten as

Do

num.Text=counter
counter=counter+1

Loop until counter>1000

9.2 For....Next Loop
The format is:


For counter=startNumber to endNumber (Step increment)

One or more VB statements

Next


Example:

(a) For counter=1 to 10

display.Text=counter

Next

(b) For counter=1 to 1000 step 10

counter=counter+1

Next

(c) For counter=1000 to 5 step -5

counter=counter-10