1. CIS 199 Test 01 Review

2. Computer Hardware  Central Processing Unit (CPU)  Brains  Operations performed here  Main Memory (RAM)  Scratchpad  Work area for programs, process, temporary data  Secondary Storage  Hard drive  Flash drive  CD, DVD

3. Input, Output Devices  Input  Takes data IN  Keyboard, Mouse, Game Controller, Microphone  Output  Pushes, places data OUT  Display, Speakers, Printers

4. Programs and Digital Data  Programs  Operating Systems. Microsoft Office, Web browsers  Instructions read by CPU and processed  Digital Data  1’s  0’s  …forms binary (base 2)

5. Built-In Types

6. Properties  Exposed “Variables” or accessible values of an object  Can have access controlled via scope modifiers  When thinking of properties: Values and definitions  “get” – Code to run before returning a value  “set” – Code to run before updating a value  Can be used for validation and other processing actions  “value” is a keyword in “set”

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

9. Scope  “private” – Can only be accessed by the class, object itself  “protected” – Can only be accessed by the class, object, or any child classes, objects  “public” – Available access for all

10. Named Constants  AVOID MAGIC NUMBERS!  Allows for reference across similar scope  Change once, changes everywhere

11. Conditional Logic  if(expression)  If ‘expression’ is true  If not true, skipped  else if(expression)  Can be used to ‘chain’ conditions  Code runs if ‘expression’ is true  else  Code to execute if ‘expression’ false  Statements can be nested

12. Relational Operators  > Greater than  < Less than  >= Greater than OR equal to  <= Less than OR equal to  == Equal to  != NOT equal to  X > Y  X >= Y  X < Y  X <= Y  X == Y  X != Y

13. Operator Precedence  (Highest)  ++, --, !  * / %  + -  =  == !=  &&  ||  = *= /= %= += -=  (Lowest)  Detailed from: http://msdn.microsoft.com/en-us/library/2bxt6kc4%28v=vs.100%29.aspx

14. Comparing Strings  You can use  ==, !=  You cannot use  >, >=, <, <=  You SHOULD use:  String.Compare(s1, s2)  s1 > s2  Returns positive Number  s1 = s2  Returns zero  s1 < s2  Returns negative number  Compares the unicode value of EACH character

15. Exceptions and Exception Handling  Exceptions are…  “Exceptional” events  Unexpected events, errors during runtime  Unhandled exceptions? Stack trace and application death  Handled with try/catch/finally blocks  Try block “attempts” to run the code in question  Catch block handles the exception(s) that may occur  Finally block, optional, always executes

18. Sample Questions

19. What does ‘WYSIWYG’ stand for?  What  You  See  Is  What  You  Get

20. What is the difference between a high-level and a low-level language?  Low-Level  Little to no ‘abstraction’ from the hardware or computer  “Close to the hardware”  Simple, but Difficult to use  Machine code, assembly, C (in some cases)  High-Level  Very strong ‘abstraction’ from the hardware or computer  “Far from the hardware”  Easier to use, abstraction adds complexity  C++, Java, C#, Python

21. How is the lifetime of a FIELD different from a lifetime of LOCAL variable?  Fields are members of their containing type  Fields can be used everywhere with appropriate scope  Local variables can be used only in their “local” environment

22. What two things does a variable declaration specify about a variable?  Type  Identifier TYPEIDENTIFIER

23. Describe ‘&&’ and ‘||’ and how they work.  && (AND)  Returns true if conditions are ALL true  “If you do well on the test AND the quiz, you will earn a great grade!”  || (OR)  Returns true if ANY conditions are true  “You can run a mile OR walk two miles (possible do both!)”

24. Why is ‘TryParse’ more effective than ‘Parse’?  Less code  No try / catch required

25. What is the difference between a SIGNED an UNSIGNED int?

26. What is the difference between syntax errors and logic errors?  Syntax Errors – Errors that prevent compilation or other factors that prevent successful compilation  striing myString = string.Empty; // Won’t compile, syntax error  Logic Errors – Errors that occur during runtime, such as incorrect comparison or other unexpected behavior  If(grade > 60) { Code if grade is F } // Incorrect operator used

27. What are the “Five logical units”?  CPU – Processing, instructions  Memory – Scratch pad, working space (Temporary)  Secondary Storage – Hard drives, storage (Long term)  Input – Keyboards, Mice, Controllers  Output – Monitors, Speakers, Printers

28. Explicit type conversion? Why and how?  Variables must be used for a single type never change  Move from one type to another, must cast  EXPLICIT cast / type conversion  Aware of information loss

29. Write a code fragment that will display “Good Job” when int variable score is 80 or more, “OK” when score is 70 – 79, and “Needs Work” for any score under 70.

30. Write a code fragment that will apply a 10% discount to the value in double variable total when int variable numItems is 5 or more and int variable zone is 1, 3 or 5.

31. Question?  ANSWER

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