Deck 7: Arrays and the Arraylist Class

Question 1

Given that String[] str has been initialized, to get a copy of str[0] with all characters converted to upper case, use the following statement:

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

Answer 1

D

Question 2

Subscript numbering always starts at what value?

A) 0
B) 1
C) -1
D) None of the above

Answer 2

A

Question 3

What do you call the number that is used as an index to pinpoint a specific element within an array?

A) subscript
B) global unique identifier
C) element
D) argument

Answer 3

A

Question 4

What would be the results after the following code was 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) This is a compilation error

Question 5

What will be the value of x[1] after the following code is executed? int[] x = {22, 33, 44};
ArrayProcess(x);
…
Public static void arrayProcess(int[] a)
{
For(int k = 0; k < 3; k++)
{
A[k] = a[k] + 5;
}
}

A) 27
B) 33
C) 38
D) 49

Question 6

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 7

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

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

Question 8

In memory, an array of String objects

A) consists of elements, each of which is a reference to a String object.
B) is always implemented as a ragged array.
C) consists of elements, each of which is a String object.
D) must be initialized when the array is declared.

Question 9

When an array is passed to a method:

A) a reference to the array is passed
B) it is passed just as an object
C) the method has direct access to the original array
D) All of the above

Question 10

What do you normally use with a partially-filled array?

A) A class that does nothing but manage the array
B) An accompanying parallel array
C) An accompanying integer value that holds the number of items stored in the array
D) An accumulator

Question 11

This indicates the number of elements, or values, the array can hold.

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

Question 12

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 13

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) All of the above

Question 14

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

A) Declares array1 to be a reference to an array of double values
B) Creates an instance of an array of 10 double values
C) Will allow valid subscripts in the range of 0 - 9
D) All of the above

Question 15

What will be the results of the following code? final int ARRAY_SIZE = 5;
Double[] x = new double[ARRAY_SIZE];
For(int i = 1; i <= ARRAY_SIZE; i++)
{
X[i] = 10.0;
}

A) All the values in the array are initialized to 10.0
B) All the values, except the first, are set to 10.0
C) An error will occur when the program runs.
D) There will be a compilation error

Question 16

To return an array of long values from a method, use this as the return type for the method.

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

Question 17

What would be the results of the following code? 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 the values in array1

Question 18

What would be the results of the following code? 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) This is a compilation error, you cannot compare array elements

Question 19

What will be the value of x[8] after the following code has been 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 20

By default, Java initializes array elements with what value?

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

Question 21

What would be the results after the following code was 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) This is a compilation error

Question 22

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 23

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 the loop 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 have an average of N/2 comparisons, where N is the number of elements in the array

Question 24

What would be the results of the following code? 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 would cause the program to crash

Question 25

What would be the results of the following code? 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 would cause the program to crash

Question 26

A ragged array is:

A) a two-dimensional array for which the number of rows is unknown
B) a one-dimensional array for which the number of elements is unknown
C) a two-dimensional array where the rows are of different lengths
D) There is no such thing as a ragged array

Question 27

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

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

Question 28

What will be returned from the following method? public static float[] getValue(int x)

A) A float value
B) An array of float values
C) An integer
D) An array of integers

Question 29

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

A) An array of 6 values ranging from 0 through 5 and referenced by the variable x will be created
B) A compilation error will occur
C) The program will crash when it is executed
D) The value of x[1] will be 0, x[2] will be 0, x[3] will be 0, x[4] will be 0, x[5] will be 0, and x[6] will be 0.

Question 30

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

A) Declares array1 to be a reference to an array of long values
B) Creates an instance of an array of 10 long values
C) Will allow valid subscripts in the range of 0 - 9
D) All of the above

Question 31

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

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

Question 32

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 33

What will be the value of x[8] after the following code has been 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 34

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 35

The sequential search algorithm:

A) requires the array to be ordered
B) must always be implemented as a method
C) uses a loop to sequentially step through an array, starting with the first element
D) will not execute, if the element is not in the array

Question 36

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

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

Question 37

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 direct access to the original array
D) All of the above

Question 38

In order to do a binary search on an array,

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

Question 39

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) 94
B) 84
C) 93
D) 95

Question 40

A search algorithm:

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

Question 41

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

Question 42

Any items typed on the command-line, separated by 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 43

Which of the following is a valid declaration for a ragged array?

A) int[] ragged = new int[5];
B) int[][] ragged = new int[5][6];
C) int[][] ragged = new int[5][];
D) int[][] ragged = new int[][5];

Question 44

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

Question 45

The following statement creates an ArrayList object. What is the purpose of the notation? ArrayList arr = new ArrayList();

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

Question 46

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

Question 47

To compare the contents of two arrays, you must compare the elements of the two arrays.

Question 48

This ArrayList class method is used to insert an item into an ArrayList.

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

Question 49

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 50

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

Question 51

Declaring an array reference variable does not create an array.

Question 52

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

Question 53

You can use this ArrayList class method to replace an item at a specific location in an ArrayList.

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

Question 54

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

Question 55

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

Question 56

You use this method to determine the number of items stored in an ArrayList object.

A) numberItems
B) capacity
C) size
D) items

Question 57

You can use this ArrayList class method to insert an item at a specific location in an ArrayList.

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

Question 58

This ArrayList class method deletes an item from an ArrayList.

A) remove
B) delete
C) erase
D) purge

Question 59

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

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

Question 60

The ArrayList class is in this package.

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

Question 61

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

Question 62

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

Question 63

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

Question 64

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