iLearn Excel VBA: Do-While-Loop

A Different Kind of Loop

A Do-While-Loop is similar to a For-Loop in the sense that they are both iteration statements. The only difference is that the Do-While-Loop has a conditional statement that it uses to determine whether or not the loop shall continue. Take a look:

Sub TheDoWhileLoop()
    Dim x As Integer
    x = 1
    Do While (x <= 10)
        Debug.Print x
        x = x + 1
    Loop
End Sub

After executing the code above you should get the integers 1-10 displayed in your immediate window. Line 4 reads exactly as it shows, keep looping while x is less than or equal to 10. We print x in line 5 and increase it’s value by 1 in line 6. Then the loop statement in line 7 sends it back to line 4. This is exactly what the For-Loop did, but instead you have to manually change the variable that is in the conditional statement, which can lead to . . .

The Loop . . . It’s Never Ending!!!

READ THIS WHOLE SECTION BEFORE TRYING THIS!! Try deleting line 6 and re-running the code. Finished yet? How about now? Notice that because we never increase the x value manually the conditional statement will always be true because x will remain 1. This is called a never ending loop. I have run into many a never ending loops in my day and unless you are a programming prodigy, you will too. There are a couple ways to get out of this never ending loop, here are a few:

Steps to take to kill your code execution:

1. Hit the Escape Key a couple times
2. Hit the Pause/Break Key a couple times
3. Press Ctrl+C a couple times
4. If none of the above key combos worked then Ctrl+Alt+Delete and kill Excel

Join me next time as I talk about the under appreciated Select-Case, signing off ~iAtoria.