do while/loop vs for loop

[lezawang]

Hi
I understand both of them but I really do not see when I need to use one over the other. Is there any example that shows we can only use one over the other? Thank you so much.

 

[mikerickson]

No there is no case where one can use a For loop, but not use a Do While.

For i = 1 to 10
    ' something
Next i

i = 1
Do While i <=10
    ' something
    i = i +1
Loop

The Do loop is prefered if the indexing variable (i in the above examples) incriments differently each loop, or where the end condition changes depending on the action of the loop.