1. CIS-166 Final
 Open book, open notes, open computer
 100 points
 True/false, multiple choice, fill-in, short
answer
 Emphasis on material since midterm

2. Arrays
 List or series of values all referenced by
the same name
 Use an array to keep a series of variables
for later processing such as
◦ Reordering
◦ Calculating
◦ Printing

3. Array Terms
 Element
◦ Individual item in the array
 Index (or subscript)
◦ Zero based number used to reference
the specific elements in the array
◦ Must be an integer
 Boundaries
◦ Lower Subscript, 0 by default
◦ Upper Subscript

4. Simple Array Example
studentNames Array
(0) Janet Baker
(1) George Lee
(2) Sue Li
(3) Samuel Hoosier
(4) Sandra Weeks
(5) William Macy
(6) Andy Harrison
(7) Ken Ford
(8) Denny Franks
(9) Shawn James

5. Dim Statement for Arrays
Default Values
string[] strName = string[4]
Results in an array of 4 elements:
strName(0), strName(1),
strName(2), strName(3)
decimal[] decBalance= new
decimal[100]
Results in an array of 100 elements:
decBalance(0), . . . , decBalance(99)

6. Dim Statement for Arrays
Assigned Values
string[] departments = {"ACT", "MKT", "HR"}
Results in an array with 3 elements, each with a value,
departments[0] is “ACT”
Integer[] intActCode = {10, 20, 30, 40}
Results in an array with 4 elements, each with a number
stored

7. Referencing Array Elements
 Use the Index(es) of the Element
strName(row)
(0) Sam Smith strName[0] : "Sam Smith"
(1) Jill Creech strName[1] : "Jill Creech"
(2) Paul Fry strName[2] : "Paul Fry"
(3) Rich Wells strName[3] : "Rich Wells"

8. Working with Arrays
 Use Loops to reference each element in
the array
◦ For / Next
◦ For Each / Next

9. For Next Loop
Assume strNames[10] already declared
integer intCounter, intEnd
intEnd = strNames.GetUpperBound(0)
For (intCounter = 0; intcounter<=intEnd;
intCounter++)
{Console.Writeline(strNames[intCounter])}

10. For Each Loop
Assume strNames[10] already declared
foreach (string Item in strNames)
{Console.Writeline(Item)]

11. Object Terminology Review
 Object - like a noun, a thing
◦ An object is based on a class
 Properties - like an adjective,
characteristics of object
 Methods - like a verb, an action or
behavior, something the object can do
 Events - object response to user
action or other events

12. Polymorphism
 Overloading: Argument type determines
which version of a method is used
◦ Example: MessageBox.Show method
 Overriding: Refers to a class that has the
same method name as its base class
◦ Method in subclass takes precedence

13. Specifying a Namespace
 Namespaces are used in .Net to organize
classes and source files
 When referring to classes in a different
namespace
◦ Write out the entire namespace
◦ Add an Imports Statement to include the namespace
Using System.Windows.Forms.Form
Namespace
Name of the Class

14. Instance versus Static Variables
 Instance variables or properties use a
separate memory location for each
instance of the object
 Static variables or properties use a single
memory location that is available for ALL
objects of a class
◦ Can be accessed without instantiating an
object of the class
◦ Use the Static keyword to create
Static Methods can also be created

15. Constructors and Destructors
 Constructor: Method that
automatically executes when an object
is instantiated
◦ Create by writing a procedure using the
Class Name, followed by any arguments
 Destructor: Method that
automatically executes when an object
is destroyed
◦ Microsoft discourages use of in .Net

16. Collections
 Group of objects
◦ Can be strongly typed: all objects based on
the same class
 Similar to an array
◦ Collection expands and contracts
automatically
 Have common properties and methods
◦ Add, Remove, Count, Item (Indexer)

17. Item Property
 Typically default property for a collection
◦ Refer to collection object, followed by
location (in [])
 Returns a member of the group
◦ Typically based on location, but can use other
values
◦ Data type depends on the type of objects the
collection manages

18. Text Data Files
 Actual data stored in files on disk
device
 File: Entire collection of data
 Records: Rows or lines, one per
entity
 Fields: Data elements (values) within a
row

19. Text File Handling
 A Stream is designed to transfer a
series
of bytes from one location to another
 Streams are objects that have
properties and methods
 Found in the System.IO namespace
 File handling projects usually contain
an Imports statement before the
statement declaring the form's class

20. Writing Data Files
 Declare a new StreamWriter object
 Use StreamWriter's WriteLine
method
 Call StreamWriter's Close method

21. Write and WriteLine Methods
 Write Method: Places items consecutively
in the file with no separator
 WriteLine Method: Places an Enter
(carriage return) between records

22. Reading Files
 Declare a new StreamReader object
◦ File must exist!
 Use StreamReader's ReadLine method
◦ Loop to retrieve multiple records
 Call StreamReader's Close method

23. ReadLine Method
 Use to read previously saved data
 Each time it executes, it reads the next
line of data
 Always assign the value from the read
to a location, such as a label, text box,
or string variable

24. Checking for End of File
 Use StreamReader's Peek Method
 Peek looks at the next element without
actually reading it
 If you Peek beyond the last element the
value returned is -1