Process:

First test the Logical Expression
If it is TRUE executes the statement
Upon reaching of key word LOOP, again checks the condition is true or false
If it is TRUE against executes the loop, it it is false it stops the execution

Do Loops - Flexible Loops

Like For Loop, Do loop's iteration doesn't fixed

Iterations of DO Loops entirely depends on satiation of Loop Determinant Condition

We can classify DO Loops in 4 ways based on Testing of Loop Determinant Condition

Do ----while Loop
Do ----until Loop

Do ----while Loop

(i)Testing condition before executing the body of the Loop

(ii)Testing condition after executing the body of the Loop

Do ----Until Loop

(i)Testing condition before executing the body of the Loop

(ii)Testing condition after executing the body of the Loop

Condition: represents to Logical Expression for Loop determinant
Statements: represents to Body of Loop

What is the difference between WHILE loop and UNTIL loop:

Do - While Loop executes when condition is TRUE
Do - While Loop doesn't execute when condition is FALSE

DO WHILE LOOP EXECUTES AS LONG AS CONDITION IS TRUE

Do - Until Loop executes when condition is FALSE
Do - Until Loop doesn't execute when condition is TRUE

DO UNTIL LOOP EXECUTES UNTIL CONDITION IS TRUE

Do Loops - Condition Execution After Loop

Testing Loop Determinant - before execution of Body

Do While Loop:

Condition: represents to Logical Expression for Loop determinant

Statements: represents to Body of Loop

If Logical expression is TRUE, then VBA executes the body

If Logical expression is FLASE, then VBA stops to executes the body

Loops iterates untill the condition is FALSE

As condition exists before the statements, sometimes Loop doesn't execute at least once(based on satiation of condition)

Print Numbers upto 10

Do Until Loop

Do While Loop

Do Until Loop - Example

Private Sub CommandButton1_Click()
Dim i As Integer
i = 1
Do Until Range("A" & i).Value = 55
Range("A" & i).Interior.ColorIndex = 3
i = i + 1
Loop
End Sub

Do Until Loop - Example

Private Sub CommandButton1_Click()
Dim i As Integer
i = 1
Do While Range("A" & i).Value <> 55
Range("A" & i).Interior.ColorIndex = 3
i = i + 1
Loop
End Sub