Loop Statements (for, while, repeat)

For statement

The For statement can be used to repeatedly execute code. It allows to iterate from low to high bounds with specified step, or even in reverse order with negative step. If the Step clause is omit, then the default step is 1.

For i = 0 To 10

  MsgBox(i)

Next

For i = 0 To 10 Step 2

  MsgBox(i)

Next

For i = 10 To 0 Step -1

  MsgBox(i)

Next
 

Do/Loop statement

The Do/Loop statement is a conditional loop statement. The statement supports While or Until conditions; and these conditions can be placed either: at the top or at the bottom of the statement. If the condition is placed at the top of the statement, then its checked before each execution (thus, even before first execution) of the loop child statements:

Dim i = 1

Do While i < 10

  MsgBox(i)

  i = i * 2

Loop

Dim i = 1

Do Until i >= 10

  MsgBox(i)

  i = i * 2

Loop
 

If the condition is placed at the bottom of the statement, then its checked after each execution (thus, only after first execution) of the loop child statements:

Dim i = 1

Do 

  MsgBox(i)

  i = i * 2

Loop While i < 10

Dim i = 1

Do 

  MsgBox(i)

  i = i * 2

Loop Until i >= 10

Exit For/Do statement

The Exit For or Exit Do statements can be used to break loop execution. Using Exit For or Exit Do statements outside of the corresponding loop is a syntax error.

Dim i = 1

Do While i < 100

  If i = 15 Then

    Exit Do

  End If

  i = F(i)

Loop

Dim sum = 0

For i = 0 To 10 

  sum = sum + i

  If sum > 15 Then

    Exit For

  End If

Next

The Exit For or Exit Do statements always works with innermost loop:

For i = 0 To 10 'outer

  If i = 5 Then

    Exit For 'Break outer loop.

  End If

  For j = 0 To 10 'inner

    If j = 5 Then 

      Exit For 'Break inner loop.

    End If

  Next

Next