ME 142
Engineering Computation I
Do Loops
Calendar Items
 VBA Exam – In Class Only

Units 3-6
 Hard deadline for VBA 6/11
Do… Loop Statement
 The Do… Loop statement is used to
repeatedly execute a block of statements until
a specified condition is met. Conditions are
tested using While and Until at either the
beginning or end of the loop.
Do… Loop Statement
Do [While condition]
[statements]
Loop
Do [Until condition]
[statements]
Loop
Do
[statements]
Loop [While condition]
Do
[statements]
Loop [Until condition]
Do
[statements]
Loop
Example Problem
 Create a factorial function using Do loops.
Pass the function the number whose factorial is
to be computed. After computing the factorial,
the results should be displayed in the cell from
which the function is called.
 Use the factorial function you created to
compute the factorials for the integers 1
through 10.
Example Problem Soln
Function factorial(n)
'computes the factorial of a number
Total = 1
I = 1
Do While I <= n
Total = Total * I
I = I + 1
Loop
factorial = Total
End Function
Do...Loop Statement
Do… Loop Statement
 The Do… Loop statement is used to
repeatedly execute a block of statements until
a specified condition is met. Conditions are
tested using While and Until at either the
beginning or end of the loop.
Do… Loop Statement
Do [While condition]
[statements]
Loop
Do [Until condition]
[statements]
Loop
Do
[statements]
Loop [While condition]
Do
[statements]
Loop [Until condition]
Do
[statements]
Loop
Do… Loop Example
x = 1
Do
Cells(x,1) = x
x = x + 1
Loop Until x = 5
x = 1
Do Until x =5
Cells(x,1) = x
x = x + 1
Loop
Do… Loop Example
x = 10
Do
Cells(x,1) = x
x = x + 1
Loop Until x = 5
Use Ctrl+Break or
Esc to stop execution
of infinite loop
Do… Loop Example
x = 10
Do
Cells(x,1) = x
x = x + 1
Loop Until x> = 5
x = 10
Do Until x >=5
Cells(x,1) = x
x = x + 1
Loop
Example Problem
 Create a factorial function using Do loops.
Pass the function the number whose factorial is
to be computed. After computing the factorial,
the results should be displayed in the cell from
which the function is called.
 Use the factorial function you created to
compute the factorials for the integers 1
through 10.
Example Problem Soln
Function factorial(n)
'computes the factorial of a number
Total = 1
I = 1
Do While I <= n
Total = Total * I
I = I + 1
Loop
factorial = Total
End Function
Review Questions
Review Question
What is the value of Count after the loop has finished
executing:
x=1
Count=0
Do
Count = Count + x
x = x + 1
Loop Until x = 5
A.
B.
C.
D.
E.
0
5
10
15
None of the above
Homework Help ‘n Hints