Deck 7: Arrays and the Arraylist Class

Question 1

A sorting algorithm is a technique for scanning through an array and rearranging its contents in some specific order.

Answer 1

True

Question 2

Objects in an array are accessed with subscripts, just like any other data type in an array.

Answer 2

True

Question 3

By default, Java initializes array elements to __________.

A) 0
B) 100
C) -1
D) 1

Answer 3

A

Question 4

Any items typed on the command line, separated by a space, after the name of the class are considered to be one or more arguments that are to be passed into the main method.

Question 5

Each array in Java has a public field named __________ that contains the number of elements in the array..

A) size
B) capacity
C) length
D) limit

Question 6

The ___________ method is used to insert an item into an ArrayList.

A) insert
B) add
C) store
D) putItem

Question 7

Subscripting always starts with __________.

A) 0
B) 1
C) -1
D) none of these

Question 8

The String [ ] args parameter in the main method header allows the program to receive arguments from the operating system command-line.

Question 9

An ArrayList object automatically expands in size to accommodate the items stored in it.

Question 10

When an array of objects is declared but not initialized, the array values are set to null.

Question 11

If a[ ] and b[ ] are two integer arrays, the expression a == b compares the array contents.

Question 12

It is common practice to use a __________ variable as a size declarator.

A) static
B) reference
C) final
D) boolean

Question 13

Java limits the number of dimensions that an array can have to 15.

Question 14

An array can hold multiple values of several different types of data simultaneously.

Question 15

A sorting algorithm is used to locate a specific item in a larger collection of data.

Question 16

Once an array is created, its size cannot be changed.

Question 17

Declaring an array reference variable does not create an array.

Question 18

To determine if two arrays are equal you must compare each of the elements of the two arrays.

Question 19

Java does not limit the number of dimensions an array may have.

Question 20

The __________ indicates the number of elements the array can hold.

A) new operator
B) array's size declarator
C) array's data type
D) version of Java

Question 21

Which of the following is a correct method header for receiving a two-dimensional array as an argument?

A) public static void passMyArray(int[1, 2])
B) public static void passMyArray(int[ ][ ])
C) public static void passMyArray[1][2])
D) public static void passMyArray(int[ ],int[ ] myArray)

Question 22

To return an array of long values from a method, which return type should be used for the method?

A) long[ARRAY_SIZE]
B) array
C) long[ ]
D) long

Question 23

A(n) __________ is used as an index to pinpoint a specific element within an array.

A) boolean value
B) element
C) argument
D) subscript

Question 24

Which of the following ArrayList class methods is used to insert an item at a specific location in an ArrayList?

A) set
B) store
C) add
D) insert

Question 25

When an individual element of an array is passed to a method __________.

A) a reference to the array is passed
B) it is passed like any other variable
C) the method does not have access to the original array
D) All of these are true.

Question 26

Java performs ____________, which means that it does not allow a statement to use a subscript that is outside the range of valid subscripts for the array.

A) active array sequencing
B) array bounds checking
C) scope resolution binding
D) buffer overrun protection

Question 27

When an array is passed to a method __________.

A) it is passed just as any other object would be passed
B) the method has direct access to the original array
C) a reference to the array is passed
D) All of these are true

Question 28

In memory, an array of String objects __________.

A) consists of elements, each of which is a reference to a String object
B) is compressed to four bytes for each element
C) must be initialized when the array is declared
D) consists of an array of references to String objects

Question 29

A ragged array is __________.

A) a two-dimensional array where the rows have different numbers of columns
B) a one-dimensional array for which the number of elements is unknown
C) a two-dimensional array for which the number of rows is unknown
D) a partially initialized two-dimensional array of ranged values

Question 30

If numbers is a two-dimensional array, which of the following would give the number of columns in row r?

A) numbers.length
B) numbers.length[r]
C) numbers[r].length
D) numbers[r].length[r]

Question 31

You can use the __________ method to replace an item at a specific location in an ArrayList.

A) set
B) remove
C) replace
D) add

Question 32

The binary search algorithm __________.

A) is less efficient than the sequential search algorithm
B) will cut the portion of the array being searched in half each time it fails to locate the search value
C) will have a maximum number of comparisons equal to the number of elements in the array
D) will, normally, have the number of comparisons that is half the number of elements in the array

Question 33

In Java, you do not use the new operator when you use a(n) ____________.

A) array size declarator
B) initialization list
C) two-dimensional array
D) any of these

Question 34

A partially filled array is normally used __________.

A) when only a very small number of values need to be stored
B) when you know how many elements will be in the array but not what the values are
C) with an accompanying parallel array
D) with an accompanying integer value that holds the number of items stored in the array

Question 35

A search algorithm __________.

A) arranges elements in ascending order
B) arranges elements in descending order
C) is used to locate a specific item in a collection of data
D) is rarely used with arrays

Question 36

In order to do a binary search on an array __________.

A) the array must first be sorted
B) you must first do a sequential search to be sure the element you are looking for is there
C) the values of the array must be numeric
D) no requirements are necessary

Question 37

The ArrayList class is in the __________ package.

A) java.arraylist
B) java.lang
C) java.array
D) java.util

Question 38

Which of the following is a valid declaration for a ragged array with five rows but no columns?

A) int[ ][ ] ragged = new int[5];
B) int[ ][ ] ragged = new int[ ][5];
C) int[ ][ ] ragged = new int[5][ ];
D) int[ ] ragged = new int[5];

Question 39

The sequential search algorithm __________.

A) returns 1 if the value being searched for is found or -1 if the value is not found
B) requires the array to be ascending order
C) uses a loop to sequentially step through an array, starting with the first element
D) must always be implemented as a method

Question 40

The __________ method removes an item from an ArrayList at a specific index.

A) remove
B) pop
C) deleteAt
D) clear

Question 41

Which of the following is a correct method header for receiving a two-dimensional array as an argument?

A) public static void passArray(int[1,2])
B) public static void passArray(int [ ][ ])
C) public static void passArray(int[1],[2])
D) public static void passArray(int[ ], int[ ])

Question 42

What is the value of scores[2][3] in the following array?
int[ ][ ] scores = { {88, 80, 79, 92}, {75, 84, 93, 80},
{98, 95, 92, 94}, {91, 84, 88, 96} };

A) 95
B) 84
C) 94
D) 93

Question 43

What would be the result after the following code is executed?
int[ ] x = {23, 55, 83, 19};
Int[ ] y = {36, 78, 12, 24};
X = y;
Y = x;

A) x[ ] = {36, 78, 12, 24} and y[ ] = {23, 55, 83, 19}
B) x[ ] = {36, 78, 12, 24} and y[ ] = {36, 78, 12, 24}
C) x[ ] = {23, 55, 83, 19} and y[ ] = {23, 55, 83, 19}
D) Nothing. This is a compile error.

Question 44

What will be the value of x[8] after the following code is executed?
final int SUB = 12;
Int[ ] x = new int[SUB];
Int y = 20;
For(int i = 0; i < SUB; i++)
{
X[i] = y;
Y += 5;
}

A) 50
B) 55
C) 60
D) 65

Question 45

What would be the result of executing the following code?
int[ ] x = {0, 1, 2, 3, 4, 5};

A) An array of 6 values, all initialized to 0 and referenced by the variable x will be created.
B) An array of 6 values, ranging from 0 through 5 and referenced by the variable x will be created.
C) The variable x will contain the values 0 through 5.
D) A compiler error will occur.

Question 46

What would be the result after the following code is executed?
final int SIZE = 25;
Int[ ] array1 = new int[SIZE];
).. // Code that will put values in array1
Int value = 0;
For (int a = 0; a < array1.length; a++)
{
Value += array1[a];
}

A) value contains the highest value in array1.
B) value contains the lowest value in array1.
C) value contains the sum of all the values in array1.
D) This code would cause the program to crash.

Question 47

What would be the result after the following code is executed? int[ ] numbers = {50, 10, 15, 20, 25, 100, 30};
Int value = 0;
For (int i = 1; i < numbers.length; i++)
Value += numbers[i];

A) The value variable will contain the average of all the values in the numbers array.
B) The value variable will contain the sum of all the values in the numbers array.
C) The value variable will contain the lowest value in the numbers array.
D) The value variable will contain the highest value in the numbers array.

Question 48

What will be the result after the following code is executed?
final int ARRAY_SIZE = 5;
Float[ ] x = float[ARRAY_SIZE];
For (i = 1; i <= ARRAY_SIZE; i++)
{
X[i] = 10.0;
}

A) A runtime error will occur.
B) All the values in the array will be initialized to 10.0.
C) All the values in the array except the first will be set to 10.0.
D) The code contains a syntax error and will not compile.

Question 49

Given the following two-dimensional array declaration, which statement is true?
int[ ][ ] numbers = new int[6][9];

A) The numbers array has 54 rows.
B) The numbers array has 15 rows.
C) The numbers array has 6 rows and 9 columns.
D) The numbers array has 6 columns and 9 rows.

Question 50

For the following code, what would be the value of str[2]?
String[ ] str = {"abc", "def", "ghi", "jkl"};

A) a reference to the String object containing "ghi"
B) "ghi"
C) a reference to the String object containing "def"
D) "def"

Question 51

What will be the results after the following code is executed?
int[ ] array1 = new int[25];
).. // Code that will put values in array1
Int value = array1[0];
For (int a = 1; a < array1.length; a++)
{
If (array1[a] < value)
Value = array1[a];
}

A) value contains the highest value in array1
B) value contains the lowest value in array1
C) value contains the sum of all the values in array1
D) value contains the average of all the values in array1

Question 52

What would be the result after the following code is executed?
int[ ] numbers = {40, 3, 5, 7, 8, 12, 10};
Int value = numbers[0];
For (int i = 1; i < numbers.length; i++)
{
If (numbers[i] < value)
Value = numbers[i];
}

A) The value variable will contain the average of all the values in the numbers array.
B) The value variable will contain the sum of all the values in the numbers array.
C) The value variable will contain the lowest value in the numbers array.
D) The value variable will contain the highest value in the numbers array.

Question 53

If numbers is a two-dimensional int array that has been initialized and total is an int that has been set to 0, which of the following will sum all the elements in the array?

A) for (int row = 1; row < numbers.length; row++)
{
For (int col = 1; col < numbers.length; col++)
Total += numbers[row][col];
}
B) for (int row = 0; row < numbers.length; row++)
{
For (int col = 0; col < numbers.length; col++)
Total += numbers[row][col];
}
C) for (int row = 0; row < numbers[row].length; row++)
{
For (int col = 0; col < numbers.length; col++)
Total += numbers[row][col];
}
D) for (int row = 0; row < numbers.length; row++)
{
For (int col = 0; col < numbers[row].length; col++)
Total += numbers[row][col];
}

Question 54

Which of the following for loops is valid, given the following declaration?
String[ ] names = {"abc", "def", "ghi", "jkl"};

A) for (int i = 0; i < names.length; i++)
System.out.println(names[i].length);
B) for (int i = 0; i < names.length(); i++)
System.out.println(names[i].length);
C) for (int i = 0; i < names.length; i++)
System.out.println(names[i].length());
D) for (int i = 0; i < names.length(); i++)
System.out.println(names[i].length());

Question 55

If final int SIZE = 15 and int[ ] x = new int[SIZE], what would be the range of subscript values that could be used with x[ ]?

A) 1 through 15
B) 1 through 14
C) 0 through 14
D) 0 through 15

Question 56

Given that String[ ] str has been initialized, to get a copy of str[0] with all the characters converted to uppercase, you would use the __________ statement.

A) str.uppercase();
B) str[0].upperCase();
C) str.toUpperCase();
D) str[0].toUpperCase();

Question 57

What will be the value of x[8] after the following code is executed?
final int SUB = 12;
Int[ ] x = new int[SUB];
Int y = 100;
For(int i = 0; i < SUB; i++)
{
X[i] = y;
Y += 10;
}

A) 170
B) 180
C) 190
D) 200

Question 58

What will be the results after the following code is executed?
int[ ] x = { 55, 33, 88, 22, 99, 11, 44, 66, 77 };
Int a = 10;
If(x[2] > x[5])
A = 5;
Else
A = 8;

A) a = 5
B) a = 8
C) a = 10
D) a = 13

Question 59

What would be the result after the following code is executed?
int[ ] x = {23, 55, 83, 19};
Int[ ] y = {36, 78, 12, 24};
For(int a = 0; a < x.length; a++)
{
X[a] = y[a];
Y[a] = x[a];
}

A) x[] = {36, 78, 12, 24} and y[] = {23, 55, 83, 19}
B) x[] = {36, 78, 12, 24} and y[] = {36, 78, 12, 24}
C) x[] = {23, 55, 83, 19} and y[] = {23, 55, 83, 19}
D) Nothing. This is a compile error.

Question 60

What would be the result after the following code is executed?
final int SIZE = 25;
Int[ ] array1 = new int[SIZE];
).. // Code that will put values in array1
Int value = 0;
For (int a = 0; a <= array1.length; a++)
{
Value += array1[a];
}

A) value contains the highest value in array1.
B) value contains the lowest value in array1.
C) value contains the sum of all the values in array1.
D) This code would cause the program to crash.

Question 61

What does the following statement do? double[ ] array1 = new double[10];

A) It declares array1 to be a reference to an array of double values.
B) It will allow valid subscripts in the range of 0 through 9.
C) It creates an instance of an array of ten double values.
D) It does all of these.

Question 62

What does specify in the following statement? ArrayList nameList = new ArrayList();

A) It specifies that String objects may not be stored in the ArrayList object.
B) It specifies that everything stored in the ArrayList object will be converted to a String object.
C) It specifies that only String objects may be stored in the ArrayList object.
D) It specifies that the ArrayList will be converted to a String array.

Question 63

Which of the following statements is(are) true about this code? final int ARRAY_SIZE = 10;
Long[ ] array1 = new long[ARRAY_SIZE];

A) It declares array1 to be a reference to an array of long values.
B) It will allow valid subscripts in the range of 0 through 9.
C) It creates an instance of an array of ten long values.
D) It will allow valid subscripts in the range of 1 through 10.