CIS 199 Test 01 Review

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 andException 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. Accepting User Inputs: GUI

19. Accepting User Input: Console

20. Sample Questions fromBlackboard Wiki

21. What does ‘WYSIWYG’ stand for? • What • You • See • Is • What • You • Get

22. GroupBox Vs Panel • GroupBoxes have: • Group Title • Panels have: • Scroll bar • Border styling options

23. 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

24. 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

25. What two things does a variable declaration specify about a variable? • Type • Identifier TYPE IDENTIFIER

26. 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!)”

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

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

29. 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

30. 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

31. 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

32. 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.

33. 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.

34. Class Vs Objects • A Class can be described as a logical collection of attributes and behaviors (methods) that describe how a group of objects “look” and behave. • An object is an instance of a class. • Classes can be viewed as templates from which objects are created e.g. building plan (class)  houses (object) • The objects from a class can share the same features and structures but can differ in implementation and use e.g. Car (Class)  RedCar (object 1), BlueCar (object 2), SilverFastCar (object 3), SilverSlowCar (object 4) class Car RedCar = new Car(“Red”, 90.0); //object 1 Car BlueCar = new Car(“Blue”, 90.0); //object 2 Car SilverFastCar = new Car(“Silver”, 100.0); //object 3 Car SilverSlowCar = new Car(“Silver”, 20.0); //object 4 Car Color MaxSpeed Accelerates() Attributes method

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