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:

Accepted Answer

The method to convert a String to upper case is to use the toUpperCase() method which is defined in the String class. Since the question specifically asks for a copy of str[0] with all characters converted to upper case, we need to select the option that applies the toUpperCase() method on the first element of the String array. Therefore, the correct answer is D, which applies the toUpperCase() method on str[0] to convert it to upper case.

Question 2

Subscript numbering always starts at what value?

Accepted Answer

Subscript numbering always starts at 0.

Question 3

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

Accepted Answer

The number used as an index to pinpoint a specific element within an array is known as a subscript.

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];
}

Accepted Answer

The answer of What would be the results after the...

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;
}
}

Accepted Answer

The method "arrayProcess" takes in an integer array "a" and adds 5 to each element of the array. In the main code, the integer array "x" is initialized with the values 22, 33 and 44. Then the method "arrayProcess" is called with the argument "x".

As a result, each element in the "x" array is incremented by 5. Therefore, the new value of x[1] will be 33 + 5 = 38. Thus, the answer is C.

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.

Accepted Answer

Java performs array bounds checking, which means that it ensures that a statement does not use a subscript that is outside the range of valid subscripts for the array. This helps prevent errors such as buffer overruns or accessing memory that is out of bounds, which can cause unpredictable behavior or crashes in the program.

Question 7

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

Accepted Answer

Using a final variable as a size declarator is common practice because once the size is set, it cannot be changed. This ensures the size remains constant throughout the program, improving stability and predictability. Static variables are not appropriate as size declarators because they are shared among all instances of a class, and using references or booleans would not accurately convey the intended meaning of the variable.

Question 8

In memory, an array of String objects

Accepted Answer

An array of String objects in memory consists of elements that are references to String objects, not the objects themselves.

Question 9

When an array is passed to a method:

Accepted Answer

When an array is passed to a method, a reference to the array is passed. Therefore, any changes made to the array within the method will be reflected in the original array (direct access). Since arrays are objects in Java, they are passed just as any other object would be. Therefore, all the given options are correct.

Question 10

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

Accepted Answer

Using an accompanying integer value that holds the number of items stored in the array is the most common and efficient way to work with partially-filled arrays. This allows you to easily keep track of the number of items stored in the array, even if it is not completely full. Using a separate class or parallel array adds unnecessary complexity, and an accumulator may not always be applicable or efficient.

Question 11

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

Accepted Answer

The array's size declarator specifies the number of elements an array can hold. The other options are not related to specifying the size of an array.

Question 12

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

Accepted Answer

The length field contains the number of elements in the array. Size is not a public field in Java arrays. Capacity and limit are not fields in Java arrays.

Question 13

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

Accepted Answer

In Java, an initialization list can be used to create and initialize an array without using the 'new' operator.

Question 14

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

Accepted Answer

The statement is declaring array1 to be a reference to an array of double values and creating an instance of an array of 10 double values. It will also allow valid subscripts in the range of 0 - 9. Therefore, all of the above options are correct.

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;
}

Accepted Answer

The code will throw an ArrayIndexOutOfBoundsException at runtime because the loop tries to access an index equal to ARRAY_SIZE, which is out of bounds for an array of size 5 (valid indices are 0 to 4).

Question 16

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

Accepted Answer

B, long[] is the correct syntax for returning an array of long values from a method. A returns only a single long value, C includes a specific size for the array which is unnecessary for the return type, and D uses incorrect syntax for declaring an array.

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];
}

Accepted Answer

The code is finding the smallest value in the array by comparing each element to the current smallest value stored in the variable 'value'. So, after the loop, the variable 'value' will contain the smallest value in the array.

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;

Accepted Answer

Since x[2] (which is 88) is greater than x[5] (which is 11), the value of a will be assigned as 5. Therefore, option A is the correct answer.

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;
}

Accepted Answer

The code initializes an array of integers named "x" with a size of 12 using the constant value 12 assigned to the variable "SUB". It also initializes an integer called "y" with the value of 100. Then it uses a for loop to iterate through the "x" array and assign each element with the value of "y". Inside the loop, the value of "y" is increased by 10. So, after the loop is executed, the value of "x[8]" will be 180, as it is the 9th element of the "x" array starting from index 0.

Question 20

By default, Java initializes array elements with what value?

Accepted Answer

Java initializes array elements with a default value of 0 if no value is specified during initialization or if the array elements are not explicitly assigned a value.

Quiz 7: Arrays and the Arraylist Class

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:

Subscript numbering always starts at what value?

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

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]; }

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; } }

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.

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

In memory, an array of String objects

When an array is passed to a method:

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

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

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

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

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

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; }

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

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]; }

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;

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; }

By default, Java initializes array elements with what value?