U2: Further Java Fundamentals

Question 1

Input Processing Output Model

Answer 1

• Entered from digital input or input device into program
• Info processed (calculations, altered, etc)
• Output to user or output device

Question 2

Process

Answer 2

• Involves manipulation, transformation of inputs
• Executing instructions, making decisions
• Assessing/modifying data structures

Question 3

Application of IPO Model

Answer 3

• Applicable across different domains of computer science
• Software development, data processing, networking

Question 4

1. Understand the Problem

Answer 4

Define problem statement; Identify inputs and outputs

Question 5

2. Design the Solution

Answer 5

• Determine steps needed to obtain input data
• Define processing required to produce desired output

Question 6

3. Implement the Solution

Answer 6

• Write code to obtain input data from user
• Implement algorithms to process input data
• Add comments

Question 7

4. Documentation

Answer 7

• Add comments to explain purpose, functionality
• Re-read comments and add additional ones

Question 8

5. Testing

Answer 8

Test program with different input values

Question 9

Variable

Answer 9

• Named location in computer’s memory
• “Named” as it’s referenced by using name
• Can be initialized by math equations

Question 10

Functions of Variables

Answer 10

• Declaring a variable = making it exist
• Initializing a variable = giving it’s first value

Question 11

Variable: int (Integer)

Answer 11

• Positive/negative #’s w/out decimals
• Between -2,147,438,648 and 2,147,438,647
• Takes 32 bits memory

Question 12

Variable: double (Double)

Answer 12

• Positive/negative #’s w/ decimals
• Up to 15 decimal places accurately
• Takes 64 bits memory

Question 13

Variable: char (Character)

Answer 13

• Single character; 16 bits memory
• Defined using single quotation marks
• Ex: ‘A’, ‘v’, ‘&’, ‘?’

Question 14

Variable: boolean (Boolean)

Answer 14

True/false; 1 bit memory

Question 15

“Not” Variable: String (String)

Answer 15

• Series of characters, words, sentences
• Memory varies by size string
• Defined using double quotation marks

Question 16

Input as String: Errors

Answer 16

• If invalid input, program can handle errors
• Allows program to validate input before conversion

Question 17

Input as String: Special Cases

Answer 17

• Allows program to handle special cases
• Ex: measurement units, prompts on context of input

Question 18

Input as String: Flexibility

Answer 18

• More flexibility over complex inputs
• Ex: multiple values, non-numeric characters

Question 19

Input as String: Parsing

Answer 19

Numeric string data must be parsed (i.e. converted) to numeric data type

Question 20

“”

Answer 20

Separates two variables with numbers by decimal with the +

Question 21

Operations in Java

Answer 21

• +: Addition
• -: Subtraction
• *: Multiplication
• /: Division
• %: Modulus (Remainer of division)

Question 22

Reserved Word

Answer 22

Word having function in Java; Ex: “int”

Question 23

Variable Name Requirements

Answer 23

• Describe what variable holds
• Must not be reserved word
• Must not be too long (ex: someInformationAboutTheUser)

Question 24

“Instantiating an object”

Answer 24

Making the object exist

Question 25

“Prompt the User”

Answer 25

Ask the user info; Read it into program

Question 26

Reading in Data From User [A]

Answer 26

Use [import java.util.Scanner;] at top of program

Question 27

Reading in Data From User [B]

Answer 27

Instantiate scanner [Scanner keyedInput = new Scanner(System.in);]

Question 28

Reading in Data From User [C]

Answer 28

Use [keyedInput.nextLine/Double/Int()] for strings, doubles, integers

Question 29

Constants

Answer 29

- Values don’t change as program runs - Use when constantly giving same value

Question 30

Constant Attributes

Answer 30

- Declared and initialized on same line - Preceded by word “final” - Have capital letters

Question 31

When to Use Constants

Answer 31

- Dates from past - Tax rates - Prices of things - Longer names - Provinces, Countries, Cities

Question 32

Rounding Techniques

Answer 32

- Multiplication/division by 10^x; x = no. of decimal values removed - variable = Math.round (variable) to nearest whole number

Question 33

Benefits of Organized Programs

Answer 33

- Easier to write; remember which subtasks already done - Easier to debug; collaborate on - Easier to maintain, update or re release

Question 34

When to Comment [A]

Answer 34

- Where variables declared and initialized - How user input generated

Question 35

When to Comment [B]

Answer 35

- Calculations, processing, formatting - Loops/selection statements

Question 36

Function of {}

Answer 36

Shows where parts of program start and end

Question 37

Function of []

Answer 37

Index arrays

Question 38

Function of ()

Answer 38

Order of operations (B in BEDMAS); provide parameters to method

Question 39

Console

Answer 39

- Allows output to screen - Doesn't allow graphics, dropboxes, text fields - Programmers test console first, then develop GUI