Exam 2

Question 1

Every value in Java is either:

A reference to an ________

One of the _____________ types

Answer 1

Object

Primitive

Question 2

Java has ___ primitive types

Answer 2

8

Question 3

Java’s primitive types are:

Four ___________

Two _________

Two _________

Answer 3

Integer types

Floating point types

Others

Question 4

Range +- 2,147,483,648 with 4 bytes

Answer 4

Int

Question 5

Range -128…127

Answer 5

Byte

Question 6

Integer type, with range -32768…32767 with 2 bytes

Answer 6

Short

Question 7

Integer type, with range +- 9,223,372,036,854,775,808 with 8 bytes

Answer 7

Long

Question 8

Floating point type, range +- 10^308 with about 15 significant decimal digits with 8 bytes

Answer 8

Double

Question 9

Single precision floating point type with a range of about +- 10^38 and about 7 significant decimal digits with 4 bytes

Answer 9

Float

Question 10

Representing code units in the Unicode encoding scheme with 2 bytes

Answer 10

Char

Question 11

Type with the two truth values false and true with 1 bit

Answer 11

Boolean

Question 12

If it is a decimal, it is a:

Answer 12

Floating-point number

Question 13

If it is not a decimal, then it is a:

Answer 13

Integer

Question 14

Generally, you use ______ for integers

Answer 14

Int

Question 15

The result of a computation exceeds the range for the number type

Answer 15

Overflow

Question 16

Occur when and exact representation of a floating point number is not possible

Answer 16

Rounding errors

Question 17

Floating point numbers have _________ precision.

Answer 17

Limited

Question 18

You should use _______ type in most cases

Answer 18

Double

Question 19

A final variable is a:

Answer 19

Constant

Question 20

Once a Constant is set, it ________ be changed.

Answer 20

Cannot

Question 21

Use all uppercase names for constants

Answer 21

Convention

Question 22

The static reserved word means that the constant _________________, not the object

Answer 22

Belongs to the class

Question 23

Give _____________ constants public access to enable other classes to use them

Answer 23

Static final

Question 24

What’s the difference between the following two statements?

final double CM_PER_INCH = 2.54;

public static final double CM_PER_INCH = 2.54;

Answer 24

The first declaration is used inside a method

The second declaration is used inside a class

Question 25

Combination of variables, literals, operators, and/or method calls

Answer 25

Expressions

Question 26

What control the order of operations

Answer 26

Parentheses

Question 27

__________ and __________ have a higher precedence than addition and subtraction

Answer 27

Multiplication | Division

Question 28

Mixing integers and floating point values in an arithmetic expression yields a:

Answer 28

Floating point value

Question 29

++ operator adds 1 to a variable called

Answer 29

Increments

Question 30

- - operator adds 1 to a variable called

Answer 30

Decrement

Question 31

What class contains methods sqrt and pow to compute square roots and powers

Answer 31

Math

Question 32

Code to compute the side length of a square whose area is stored in the variable area?

Answer 32

double sideLength = Math.sqrt(area);

Question 33

The compiler disallows the assignment of a _________ to an _____ because it is potentially dangerous

Answer 33

Double | Int

Question 34

long rounded = Math.round(balance); balance = 13.75 What is the output?

Answer 34

14

Question 35

A static method ___________ operate on and object

Answer 35

Does not

Question 36

Where are static methods declared?

Answer 36

Inside classes

Question 37

__________ has minimal set of features and must be combined with other classes to be useful

Answer 37

System.in

Question 38

Use the class called ________ to read keyboard input

Answer 38

Scanner

Question 39

What’s wrong with the following statement sequence? System.out.print(“Enter unit price: “); double unitPrice = in.nextInt();

Answer 39

Second statement calls nextInt, not nextDouble

Question 40

A ___________ is a sequence of characters

Answer 40

string

Question 41

A string of length 0 is called the:

Answer 41

Empty string

Question 42

Code to print He said “Hello”

Answer 42

“He said \”Hello\””

Question 43

Code to print C:\Temp\Secret.txt

Answer 43

“C:\\Temp\\Secret.txt”

Question 44

A character is a value of the type:

Answer 44

Char

Question 45

Character literals are delimited by _______ quotient marks

Answer 45

Single

Question 46

How to code a constant in a method?

Answer 46

final int SEATS = 100;

Question 47

How to code a constant in a class?

Answer 47

public static final int SEATS = 100;

Question 48

6/3

Answer 48

3

Question 49

5/2

Answer 49

2

Question 50

5.0/2

Answer 50

2.5

Question 51

5%2

Answer 51

1

Question 52

6%2

Answer 52

0

Question 53

How to call square root of 16?

Answer 53

Math.sqrt(16)

Question 54

How to call 2pi

Answer 54

Math.PI*2

Question 55

Double n = 3.888; | System.out.print((int)n);

Answer 55

This is casting Answer is 3

Question 56

(double) (2/5) (double) 2/5 (char) 97

Answer 56

Casting 0.0 0.5 ‘a’

Question 57

System.outprintf(“%6s”, “A”);

Answer 57

_ _ _ _ _ A

Question 58

System.out.printf(“%6.3f”, 8.7698);

Answer 58

- - 8 . 7 7

Question 59

“A” + “B” + 3 + true What is this and what is the outcome

Answer 59

Concatenation “AB3true”-it’s a whole string

Question 60

What’s the difference between 1. In.nextLine(); And 2. In.next();

Answer 60

1. Stops after whole string is acquired | 2. Stops when it reaches white space

Question 61

What are all 5 escape sequences

Answer 61

``` “\n” “\t” ‘\n’ \” \\ ```

Question 62

How to print “hi” with quotes?

Answer 62

Use \”

Question 63

How can you print a backslash? \

Answer 63

\\

Question 64

String day = “Thursday”; Char letter = day.charAt(1); What is the output?

Answer 64

‘h’

Question 65

String day = “Thursday”; Char letter = day.charAt(day.length()-1); What is the output?

Answer 65

‘y’

Question 66

String day = “Thursday”; day.substring(0,5); What is the output?

Answer 66

Thurs

Question 67

String day = “Thursday”; day.substring(5); What is the output?

Answer 67

day

Question 68

How do you code an if statement?

Answer 68

``` if(condition(s)) { Code 1 } else { Code 2 } ```

Question 69

How do you code an else/if statement?

Answer 69

``` if(conditions(s)) { Code 1 } else if(condition(s)) { Code 2 } else { Code 3 } ```

Question 70

How do you code a nested else/if statement?

Answer 70

``` If(condition(s)) { Code 1 } else { If(condition(s)) { Code 2 } else { Code 3 } } ```

Question 71

&&

Answer 71

And

Question 72

||

Answer 72

Or

Question 73

!

Answer 73

Not

Question 74

What is the order in which &&,||, and ! Is conducted?

Answer 74

! || &&

Question 75

What are 2 ways to compare strings?

Answer 75

.equals | .compareTo

Question 76

What does .conpareTo return?

Answer 76

Numbers

Question 77

Is null an object?

Answer 77

No

Question 78

Can null = “”?

Answer 78

No

Question 79

Can “null” = “”

Answer 79

Yes

Question 80

“null” = null?

Answer 80

No

Question 81

How do you check to see if a user input is an int?

Answer 81

hasNextInt() ``` If(in.hasNextInt()) { Int n = in.nextLine(); Code } ```

Question 82

A ________ is a sequence of Unicode characters. Ex.”H”

Answer 82

String

Question 83

Character __________ are delimited by single quotation marks.

Answer 83

Literal

Question 84

Relational operators have ________ precedence then arithmetic operators

Answer 84

Lower

Question 85

== tests if two strings are stored in the same:

Answer 85

Memory location

Question 86

compareTo method compares strings in :

Answer 86

Lexicographer order - dictionary order

Question 87

== operator tests whether two ________ are identical

Answer 87

Object references