1. Prepred By: Deborah Becker
VB STRINGS
Chapter 3.4
Dale Carnegie Training® can help you manage the sweeping changes that continue to reshape the workplace. Organizations today need managers who are knowledgeable business partners skilled at managing change. As change agents, managers can play a vital role in helping their organizations remain competitive.
Rely on the following process, and you will be more effective in managing organizational change.
Be sure you have earned the right to deliver this program, are excited about the topic, and are eager to share with your audience.
Speak from your own experiences. Set a good example. Help others benefit from what you have learned about managing organizational change.
1/2/2019
Prepred By: Deborah Becker

2. Prepred By: Deborah Becker
What is a string?
A String Constant is a sequence of characters that is treated as a single item.
A string’s content can be altered with an assignment statement
It can be displayed using the print statement
It can be combined using the & symbol
Start by articulating a clear vision of what your organization should be. Present the vision clearly, and explain why it is important for your organization to achieve this vision.
Include a picture of the leadership skills this vision will require. For example, global thinking, strategic partnering, etc.
1/2/2019
Prepred By: Deborah Becker

3. Prepred By: Deborah Becker
String Variables
A name used to refer to a string (DATA ELEMENTS IN A FILE).
Allowable naming conventions are the same for string and numeric variables
Once you’ve communicated where you want to go, estimate how close you are to achieving the vision. Identify strengths of the organization. Also note areas where improvements must be made to bring you closer to the vision.
Be sure to include the “As Is” of leadership strengths and areas for improvement. Organizations don’t change, people do.
1/2/2019
Prepred By: Deborah Becker

4. Naming Rules and Conventions
Identifier type Prefix
Identifier (name) 1 to 255 characters
Can use Letters, digits, underscores
Cannot use spaces, or reserved words
(Print, Name, Value, Sub, etc.)
Naming convention requires:
1) Identifier is meaningful -- A name that indicates the purpose
2) Begins with lowercase prefix specifying data type  
Starting with VB 6.0 the lowercase prefixes are now three letters as per the Microsoft MSDN Library
e.g., str  for string
int  for integer cur  for currency
For variables, capitalize each word of name after prefix
e.g.,          curHoursWorked
For constants, use full uppercase and underscore
e.g.,          curMINIMUM_WAGE
strSocialSecurityNumber
strLastName
strAddress
strCOMPANY_NAME (constant)
1/2/2019
Prepred By: Deborah Becker

5. Prepred By: Deborah Becker
Naming Conventions
bln
Boolean
cur
Currency
dbl
Double
dtm
Date
int
Integer
lng
Long
sng
Single
str
String
vnt
Variant (default)
Refer back to your naming conventions handout. Two types of variable can be string– string and variant
1/2/2019
Prepred By: Deborah Becker

6. Which of these examples follow the naming rules?
strSub
Caption
conMaximum
MinimumRate
curMaximumCheck
strCompanyName
omitted
int#Sold
i Number Sold
int.Number.Sold
sng$Amount
Sub
1/2/2019
Prepred By: Deborah Becker

7. Which of these examples follow the naming rules?
7. strSub
8. Caption
9. conMaximum
10. MinimumRate
11. curMaxCheck
12. strCompanyName
omitted
int#Sold
i Number Sold
int.Number.Sold
sng$Amount
Sub
Does not indicate the data type
Cannot contain special characters such as #
No Blank spaces are allowed within an identifier
The periods separate items like objects and properties and should not be used in a variable name
Cannot contain special characters like $
Sub us a reserved word in Visual Basic
Valid name. May not be a meaningful name
Caption is a property name and therefore a reserve word
Follows the naming rules but not the convention. A prefix should be used to indicate the data type.
A prefix should be used to indicate the data type
Valid
1/2/2019
Prepred By: Deborah Becker

8. Identify these variable types
dtmStoreHours
curSalary
strLastName
blnPrerequisite
vntFirstName
sgnPayRate
lngCityPopulation
1/2/2019
Prepred By: Deborah Becker

9. If a Variable is in Scope
When an identifier is in scope you cans read and set it’s values
If it is out of scope you will not be able to access it
Global variables are in scope from any where with in your program
Modular variable are in scope within the module where they are declared
Local variable can only be access in the procedure where they are declared
1/2/2019
Prepred By: Deborah Becker

10. Prepred By: Deborah Becker
Rules!!!!!!!!!!!!!!!!!!
It is good programming technique to limit the scope of your variables to the most restrictive scope you can use
If data needs to be maintained independently use module level variables
1/2/2019
Prepred By: Deborah Becker

11. Prepred By: Deborah Becker
Coding efficiencies
Avoid the use of variants
Variants are generally VB’s slowest data type
Use integer variables where possible
Integers and long integers are fast because they are the native data type of the computer hardware
1/2/2019
Prepred By: Deborah Becker

12. Assignment statements
strCOMPANY_NAME = “ADVENTURE UNLIMTED”
When you use an assignment statement you are setting the leftside of the = sign equal to the rightside.
The right side of the = sign must be contained in “” for a string literal
1/2/2019
Prepred By: Deborah Becker

13. Write the correct Assignment
Set the strCompanyName equal to
Ford Motor Company
Set the caption property of the lblMessage equal to
strCompanyName = “Ford Motor Company”
lblMessage.Caption = “Have a Nice Day”
1/2/2019
Prepred By: Deborah Becker

14. Correct this Procedure
Private Sub cmdCompute_Click()
Dim interestRate As Single
Dim principle As Single
Dim phrase As String
picBalance.Cls
interestRate =
100 = principle
phrase = “The loan balance is “
picBalance.Print phrase;(1 + interestRate) * principle
End Sub
1/2/2019
Prepred By: Deborah Becker

15. Prepred By: Deborah Becker
Private Sub cmdCompute_Click()
Dim sngInterestRate As Single
Dim sngPrinciple As Single
Dim strPhrase As String
picBalance.Cls
sngInterestRate =
sngPrinciple = 100
strPhrase = “The loan balance is “
picBalance.Print strPhrase;(1 + sngInterestRate) * _
sngPrinciple
End Sub
1/2/2019
Prepred By: Deborah Becker

16. Prepred By: Deborah Becker
Strings
The string that contains no characters is called a null string or empty string
A string defined as “ “ is not an empty string because it contains one space
Assigning a string value to a numeric variable can result in the error message Type mismatch
1/2/2019
Prepred By: Deborah Becker

17. Prepred By: Deborah Becker
Strings
In VB 6.0 the maximum allowable characters in a string is about
2 Billion
Declaring variable is optional with VB but not in this class
All variables must be declared with a DIM statement in the proper area.
1/2/2019
Prepred By: Deborah Becker

18. Prepred By: Deborah Becker
Strings
Variable not declared are considered to be Implicitly declared
You can display the type of a variable by
Positing the mouse over the top of the word (variable)
Press the Right Mouse button and
Clicking on Quick Info
1/2/2019
Prepred By: Deborah Becker

19. The Val Function & Str Function
You can convert the content of a textBox to a numeric value by using the Val Function
numVal = Val(txtBox.Text)
You can convert the content of a numeric variable to string by use of the Str Function
txtBox.Text = Str(intVal)
1/2/2019
Prepred By: Deborah Becker

20. Prepred By: Deborah Becker
VB Handling
You can omit the Val and Str functions from your code and VB will handle the conversion for you, BUT
intGrade = txtBox1.Text + txtBox2.Text
If the value of txtBox1 = 34 and the value of txtBox2 = 56 then the computer would assign you a grade of
3456 and not 90
1/2/2019
Prepred By: Deborah Becker

21. Prepred By: Deborah Becker
VB Handling
Evaluating a txtBox that is empty in a numeric equation in your program will result in an error message
1/2/2019
Prepred By: Deborah Becker

22. Prepred By: Deborah Becker
ANSI Character Set
Refer to appendix A in the back of your book.
Each letter, number or special character has a numeric value assigned to it.
Upper and lower case letters have different values.
Upper case letter have a lower numeric value then lower case letters.
1/2/2019
Prepred By: Deborah Becker

23. Prepred By: Deborah Becker
Evaluating the ANSI
“Cat” = “cat”
“Cat” > “cat”
“Cat” < “cat”
“big” > “Big”
“A” > “a”
“Z” < “a”
1/2/2019
Prepred By: Deborah Becker

24. Prepred By: Deborah Becker
Homework
Do Exercises 3.4 page 93-94
Do Exercises 23, 26 page 95
1/2/2019
Prepred By: Deborah Becker