Chapter 2 - Using Data

Question 1

When data cannot be changed after a class is compiled, the data is _____________.

a) variable

b) constant

c) volatile

d) mutable

Answer 1

constant

a data item is constant when its value cannot be changed while a program is running; ex) when you include the following statement in a Java class, the number 459 is a constant
System.out.println(459);

Question 2

Which of the following is not a primitive data type in Java?

a) boolean

b) byte

c) sector

d) int

Answer 2

sector

boolean, byte and int are all primitive data types in Java; Java provides for 8 primitive types of data; a primitive data type is a simple data type;

1) byte - byte length integer (8-bits)
2) short - short integer
3) int - integer
4) long - long integer
5) float - single-precision floating point
6) double - double-precision floating point
7) char - a single character
8) boolean - a boolean value (true or false)

Question 3

Which of the following elements is not required in a variable declaration?

a) a type

b) an identifier

c) an assigned value

d) a semicolon

Answer 3

an assigned value

a data type that identifies the type of data that the variable will store; an identifier that is the variable’s name; an ending semicolon

an optional assignment operator and assigned value, if you want a variable to contain an initial value

Question 4

The assignment operator in Java is _____________.

a) =

b) ==

c) :=

d) ::

Answer 4

A

the equal sign is the assignment operator; any value to the right of the assignment operator is assigned to the memory location named on the left; an assignment made when you declare a variable is an initialization; an assignment made later is simple an assignment

Question 5

Assuming you have declared shoeSize to be a variable of type int, which of the following is a valid assignment statement in Java?

a) shoeSize = 9;

b) shoeSize = 9.5;

c) shoeSize = “nine”;

d) shoeSize = 9.5F;

Answer 5

A

because the value is declared as int variable then the assigned value must be a whole integer therefore B would be incorrect as 9.5 would need to be initialized as a float; C is being initialized as a string value;

Question 6

Which of the following data types can store the value 0 using the least amount of memory?

a) short

b) long

c) int

d) byte

Answer 6

byte

a byte has a minimum value of -128 and maximum value and occupies 1 byte or 8-bits

Question 7

A boolean variable can hold _____________.

a) a character

b) a whole number

c) a decimal number

d) the value true or false

Answer 7

D

the value true or false

Question 8

The value 137.68 can be held by a variable of type _____________.

a) int

b) short

c) double

d) byte

Answer 8

C

double - a double data type requires more memory than a float and can hold 14 or 15 significant digits of accuracy; the maximum value of a double data type is 1.7 * 10^308 and the minimum is -1.7 * 10^308

Question 9

An escape sequence always begins with a(n) _____________.

a) e

b) forward slash

c) backslash

d) equal sign

Answer 9

C

a backslash

Question 10

Which Java statement produces w on one line and xyz on the next line?

a) System.out.println(“wxyz”);

b) System.out.println(“w” + “xyz”);

c) System.out.println(“w\nxyz”);

d) System.out.println(“w\nx\ny\nz”);

Answer 10

C

the “\n” is an escape sequence for a newline or linefeed; moves the cursor to the beginning of the next line

Question 11

The remainder operator _____________.

a) is represented by a forward slash

b) must follow a division operation

c) provides the quotient of integer division

d) is represented by a percent sign

Answer 11

D

The percent sign is the remainder operator . The remainder operator is most often used with two integers, and the result is an integer with the value of the remainder after division takes place. For example, the result of 45 % 2 is 1 because 2 goes into 45 twenty-two times with a remainder of 1. Other examples of remainder operations include the following:

39 % 5 is 4 because 5 goes into 39 seven times with a remainder of 4.

20 % 3 is 2 because when 20 is divided by 3, the remainder is 2.

36 % 4 is 0 because there is no remainder when 4 is divided into 36.

Question 12

Which of the following operators has the lowest precedence?

a) multiplication

b) remainder

c) subtraction

d) division

Answer 12

C

• (mulitiplication) / (division) and % (remainder) have the highest precedence

+ (addition) - (subtraction) have the lowest precedence

Question 13

The equal to relational operator is _____________.

a) =

b) ==

c) !=

d) !!’

Answer 13

B

the equal sign is a Java keyword used for variable assignments; in order to compare values being equal to one another you must use the double equal sign (==)

Question 14

When you perform arithmetic with values of diverse types, Java _____________.

a) issues an error message

b) implicitly converts the values to a unifying type

c) requires you to explicitly convert the values to a unifying type

d) implicitly converts the values to the type of the first operand

Answer 14

B

Java automatically converts nonconforming operands to the unifying type; an implicit conversion is also called a promotion

the highest level of unifying type is double followed by float followed by long; int is the lowest unifying type

Question 15

If you attempt to add a float, an int, and a byte, the result will be a(n) _____________.

a) float

b) int

c) byte

d) error message

Answer 15

A

float has the highest level unifying type in Java

Question 16

You use a _____________ to explicitly override an implicit type.

a) mistake

b) type cast

c) format

d) type set

Answer 16

B type cast

type casting forces a value of one data type to be used as a value of another type; to perform a type cast, you use a cast operator, which is created by placing the desired result type in parenthesis

float weeklyBudge = (float) (bankBalance / 4);

Question 17

In Java, what is the value of 3 + 7 * 4 + 2?

a) 21

b) 33

c) 42

d) 48

Answer 17

B

because of the order of operations precedence the multiplication would be calculated first (7*4) and then that product is added to 3 and finally 2 so 28+3+2 = 33

Question 18

Which assignment is correct in Java?

a) int value = (float) 4.5;

b) float value = 4 (double);

c) double value = 2.12;

d) char value = 5c;

Answer 18

C

Question 19

Which assignment is correct in Java?

a) double money = 12;

b) double money = 12.0;

c) double money = 12.0d;

d) All of these are correct.

Answer 19

B

double money = 12; <- this should be declared as an int

double money = 12.0d; <- this will result in an error

Question 20

Which assignment is correct in Java?

a) char aChar = 5.5;

b) char aChar = “W”;

c) char aChar = ‘*’;

d) char aChar = $;

Answer 20

C