1. CIS 199 Test 02 Review

2. Loops for while do – while foreach
“For a given value X, while X is true, modify X…”
while
“While X is true…”
do – while
“Do these tasks, while X is true…”
foreach
“For every X in this set of Y do the following…”

3. for Example

4. while Example

5. do while Example

6. foreach Example

7. Key Loop Details Loops are NOT guaranteed to execute at least once!
…only exception is ‘do while’
‘for’ loops require a variable, condition, and ‘step’ instruction
‘while’, ‘do while’ loops require a boolean expression
‘foreach’ loops require a collection of items
Arrays
Lists
Generic Collections

8. Files OpenFileDialog SaveFileDialog BOTH very User friendly!
Used to load file from location
SaveFileDialog
Used to select file save location
BOTH very User friendly!

9. OpenFileDialog

10. OpenFileDialog

11. SaveFileDialog

12. SaveFileDialog

13. Random Numbers in C# Provided from: System.Random
Is ONLY pseudo-random
Produces a finite set of values with equal probability
Not truly random, follows a mathematical algorithm
Created with OR without seed value
Common methods used:
Next()
Next(int)
Next(int, int)
NextDouble()

14. Creating and using a Random Object

15. Usage & Expected Results of Random Methods

16. Methods Actions, code to be executed
May return a value, may take value (not required)
Can be controlled via scope keywords
Can be static

17. Methods & Modularizing Your Code
Break out ‘steps’
Easier to test
Easier to visualize

18. Methods & Modularizing Your Code Example

19. Arrays

20. Arrays

21. Sample Questions from Blackboard Wiki

22. The ‘switch’ statement can replace nested if/else
The ‘switch’ statement can replace nested if/else. But under what conditions?
When matching on a specific…
Value
Type
Enumeration
…other data

23. What does a ‘break’ statement do in a loop?
It stops (BREAKS) loop execution
Code continues, no further loop iterations

24. What does a ‘continue’ statement do in a loop?
Goes to the next iteration
CONTINUES loop execution, by skipping current iteration

25. What are preconditions and postconditions for a method?
Conditions that MUST be TRUE before method execution
POSTCONDITIONS
Conditions that WILL be TRUE after method execution

26. What is the difference between a void method and a value-returning method?
Returns nothing!
…a void return.
Value-Returning
Returns a value!
…that’s not a void return.

27. Compare and contrast the use of pass by value against pass by reference, using key word ref versus pass by reference using keyword out.
Pass by Value
Passes a copy of the value
Not the object itself
Pass by Reference
Passes the actual object itself
‘ref’
Causes a pass by reference on a variable
‘out’
Is used to reference a variable that the method will update

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