1. Controlling Program Flow
091700

2. Topics
Conditional Operators
Logical Operators If
Select Case
Loops

3. Operators manipulate data by combining or computing results.

4. Math and String Operators
Already Covered
( ) ^
* / \ MOD
+ -
&

5. 6 Conditional Operators
= Equal to
< Less than
> Greater than
<> Not equal (less than or greater than)
<= Less than or equal to
>= Greater than or equal to NOTE: Errors is textbook table 6.1

6. You can compare strings
“S” < “s”
“Kev” < “Kevin”
ASCII table for character values Appendix C, page 888
IMPORTANT: The computer ultimately gives comparisons a TRUE or FALSE answer.
print (1<2)
print (1=2)

7. Like Operator Used for seeing if strings are similar
Uses Wildcards: * ? # [characters] [!not these characters]
print “Kevin” like “Ke*”
print “Boot” “B??t”
print “Beet” like “B??t”
print “Employee 7” like “Employee #”
NOTE: Wildcard comparison has to be AFTER the like operator. Book is misleading here.

8. Logical Operators
And Or
Xor
Not

9. And …Statements If (varA = varB) And (varC < varD) then End if
If True and True then
Condition 1 AND Condition 2

10. Or …Statements If (varA = varB) Or (varC < varD) then End if
If True Or True then
Condition 1 AND Condition 2

11. Xor …Statements If (varA = varB) Xor (varC < varD) then End if
If True Xor True then
Condition 1 AND Condition 2

12. Not …Statements If Not((varA = varB) And (varC < varD)) then End if
NEGATES a condition
Use Sparingly!

13. Truth Table
Condition
Result
AND
TRUE
FALSE OR
XOR

14. Such a simple device… Computers only know: 1 or 0 ON or OFF Yes or No
True or False
We combine these choices to set the course of our computer program.

15. If then If (condition is true) then do this End if

16. If then Else If (condition is true) then do this Else
do something else
End If

17. If then ElseIf If (condition is true) then do this
ElseIf (condition is true) then
do something else
Else
do yet something else
End If

18. Select Case Simpler, more logical than using several elses
Select Case varAge
Case Is <5
statements
Case 5
Case 6 to 11
Case 12 to 13, 23 to 46, Is 65
Case Else
End Select

19. For Next Loop
Used for counting through a certain number of iterations (geek-speak for times).
For Counter = 1 to 10
statements
Next

20. Nesting Loops For outerCounter = 1 to 10 statements
For innerCounter = 1 to 10
Next innerCounter
Next outerCounter

21. Step value For counter = 0 to 10 step 2 statements Next

22. Step Values: negative
For counter = 10 to 0 Step -1
statements
Next

23. Do Loops Execute WHILE a condition is true, or UNTIL it is true
Do While strAnswer=“yes”
statements
Loop

24. Do Loops Do
While
Loop
condition
Until

25. Do Loops Do While condition statements Loop Do statements
Loop While condition
Do Until condition statements
Loop Do
statements
Loop Until condition

26. An early exit… Exit Sub Exit Function Exit For Exit Do
Use sparingly - It is most clear to have one exit for a program segment