Deck 8: Single-Dimensional Arrays

Question 1

We use the new keyword to instantiate an array using an initialization list.

Answer 1

False

Question 2

Before we can instantiate objects inside an array, we must first instantiate the array.

Answer 2

True

Question 3

In order to find the maximum value of an element in an array, we must use the maxVal variable.

Answer 3

False

Question 4

To avoid encapsulation problems resulting from shared array references, it may be necessary to copy the elements of the array into a new or temporary array.

Question 5

An Insertion Sort works by implementing a triple loop.

Question 6

During an Insertion Sort, the value of the element that we are currently inserting (at index i) is stored in some temporary variable.

Question 7

An Insertion Sort runs much more efficiently than a Binary Search.

Question 8

During a Selection Sort, a portion of an array is known as a(n) __________.

Question 9

We want to store the number of referrals to our website from the top four search engines (Google, Yahoo, Bing, and Ask). Which of the following array declarations would you use?

A) int [] searchEngineReferrals;
B) int [4] google, yahoo, bing, ask;
C) int [ ] google, [ ] yahoo, [ ] bing, [ ] ask;
D) None of these is correct.

Question 10

When we declare an array, we also allocate memory for the array at the same time.

Question 11

Considering the functionality of length in an array, which of the following statements is true?

A) length functions as an instance variable.
B) length functions as a method.
C) length is always a double.
D) size and length can be used interchangeably.

Question 12

The last element in an array always has an index of 1 less than the number of elements.

Question 13

What kind of loop is generally employed to print every element of an array, in order?

A) for loop
B) while loop
C) infinite loop
D) zero loop

Question 14

The statement for ( int i = 0; i <= arrayName.length; i++ ) has generated a runtime exception. What would the corrected syntax look like?

A) for ( int i = 0; i <= arrayName.length; ++i )
B) for ( int i = 1; i < arrayName.length; i++ )
C) for ( int i = 0; i < arrayName.length( ); i++ )
D) for ( int i = 0; i < arrayName.length; i++ )

Question 15

Which of the following is not an attribute of arrays when used in user-defined classes?

A) They are an instance variable.
B) They are a parameter to a method.
C) They share references with the client.
D) They are a method.
E) They are a local variable inside a method.

Question 16

When defining a method that takes an array as a parameter, we use the following syntax:
accessModifier returnType methodName( arrayName )

Question 17

Which of the following statements is not true of a Selection Sort algorithm?

A) It loops through the elements of an array multiple times.
B) It re-orders the elements of an array in ascending or descending order.
C) It stops looping when the subarray has only one element left.
D) It indicates when it is finished by returning -1.

Question 18

Parallel arrays are best used when we have lists of items of the same length with different data types.

Question 19

Suppose we want to track the winning lottery numbers (ranging from 1 to 72) and count the number of times each number comes up over the course of a month. In this scenario, we would be wise to:

A) set up an array of counters with 72 elements.
B) set up 72 counters with if/else statements.
C) set up an array of counters with 72 elements and set up 72 counters with if/else statements.
D) None of these is correct.

Question 20

In a lottery number tracking scenario, in which the number 0 is not a possible winning number and thus would never be counted, it would be wise to create an array with one additional element and ignore element 0 altogether.

Question 21

Assume we have a situation where the number of inputs cannot possibly be determined until run time. The Java feature that we would use to specify that the method accept a variable number of arguments is called:

A) varparam.
B) varargs.
C) varinput.
D) varoutput.

Question 22

When we have a parameter specified by a method using the varargs syntax, that parameter must be listed as the first one in the method header.

Question 23

When we instantiate an array:

A) we allocate memory for the array.
B) the elements are given initial values.
C) we use the keyword new.
D) All of these are correct.

Question 24

To compare the elements of an array for equality, which of the following actions must we take first?

A) First, make a backup copy of the two arrays.
B) First, make sure the two arrays are the same length.
C) First, run a for loop to compare each array, element to element.
D) None of these is correct.

Question 25

Which of the following is not a method used to display array data as a bar chart?

A) setFill method
B) fillRect method
C) barStart method
D) fillText method

Question 26

At the beginning of a Selection Sort, the entire unsorted array is considered to be a subarray.

Question 27

In the header public static void main( String [ ] args ), the main method receives a String ____________ as a parameter.

Question 28

The position of an element within an array is known as its __________.

Question 29

The compareTo method of the String class compares the values of two ____________.

Question 30

The sorting algorithm that mirrors inserting cards one at a time into a hand is called __________.

Question 31

Suppose you are looking for the name of your friend, Mike Jones, in the telephone directory. You open the book in the middle and look at the name at the top of the left page; it starts with an L. You mark that page and look halfway between the first page and that page. As you continue to apply this strategy, you are using the _____________ algorithm.

Question 32

Where is the error in the array declaration int [5] numbers;?

A) There is no error.
B) The square brackets should be empty.
C) There should be no space between int and [.
D) It should be int numbers[5];.

Question 33

To access the element at index i of an array named grades, we use:

A) grades.
B) grades[ i ].
C) grades( i ).
D) grades{ i }.

Question 34

If an array has n elements, then the last index is:

A) n.
B) n + 1.
C) n − 1.

Question 35

Which of the following would we use to access the number of elements in an array named grades?

A) grades
B) grades.size( )
C) grades.size
D) grades.length( )
E) grades.length

Question 36

When processing all the elements of an array named grades using a for loop, what is the for loop header?

A) for( int i = 1; i <= grades.length; i++ )
B) for( int i = 1; i < grades.length; i++ )
C) for( int i = 0; i <= grades.length; i++ )
D) for( int i = 0; i < grades.length; i++ )

Question 37

When computing the maximum value in an array of integers, you should initialize the maximum value to:

A) 0.
B) 1.
C) the first element in the array.
D) 100.

Question 38

Which of the following is correct regarding the method header public static void main( String [ ] args )?

A) args is an array of Strings
B) args is a String
C) args is a void array
D) main is an array

Question 39

Insertion Sort uses a:

A) single loop.
B) double loop.
C) triple loop.

Question 40

In an array, we can have a mix of integers and Strings.

Question 41

When declaring an array, we use a set of square brackets.

Question 42

We can instantiate an array by assigning values when the array is declared.

Question 43

We cannot combine the declaration and instantiation of an array into one statement.

Question 44

It is possible to have an array of objects.

Question 45

To process all the elements of an array, we use a loop.

Question 46

To compare two arrays for equality, you call the equals method with the first array and pass the second array as the argument.

Question 47

An array can be an instance variable of a class.

Question 48

A method cannot return an array.

Question 49

We can pass an array parameter to a method.

Question 50

When we instantiate an array, we use the keyword __________.

Question 51

Looking for a value in an array by looping through all the elements of an array in order is called a(n) __________.

Question 52

What happens if you try to access an array element using a negative index or an index greater than or equal to the number of elements in the array?

Question 53

Why is a NullPointerException generated after the following statements are executed?
String [] words = new String[10];
System.out.println( words[0].length( ) );

Question 54

How do you copy an array into another array?

Question 55

How do you compare two arrays for equality?

Question 56

Name two algorithms for sorting arrays.

Question 57

We have made an array declaration of double dailyWindSpeeds [ ]; What is another valid way of writing this same declaration with an alternative syntax?

Question 58

When an array is created with the new operator, the elements of the array are automatically assigned default values. Can you identify those values for numeric elements, boolean elements, char elements, and object references?

Question 59

What is the primary difference in functionality between .length used in an array and length ( ) used in Strings?

Question 60

Under what conditions are ArrayIndexOutOfBounds exceptions generated?

Question 61

If we use the following code to make a separate copy of the array called testScores, will it work? Why or why not?
int [ ] testScores = {95, 100, 89, 92, 25};
int [ ] copyOfTestScores = testScores;

Question 62

Assume that we have an array called propertyTaxes whose elements are objects. Using a for loop, we make a copy of that array called propertyTaxesCopy. When an object in propertyTaxes changes, does it have any effect on the object in propertyTaxesCopy? Why or why not?

Question 63

Explain how the Sequential Search algorithm works within unsorted arrays.