Java Arrays Quiz: Declaration and Initialization Practice

Questions and Answers

What is the correct way to create an array with 20 double elements?

double[] array = new double[20]; (correct)

double[] array = new double();

double array = new double[20];

double array = new double[];

Given the declaration 'int[] array = {4, 3, 5, 2, 0};', what is the value of 'array[2]'?

5 (correct)

Which statement would cause a run-time error for the declaration 'int[] array = {4, 3, 5, 2, 0};'?

double[] array = new array;

double[] array = new double; (correct)

double array = new double[];

double array = new double;

What output is generated by the code segment below:

int[] values = new int; for (int k = 0; k < values.length; k++) { values[k] = k * 2; } System.out.println(values);

[2] Signup and view all the answers

To initialize array elements with values from 1 to 100, which statement should be inserted in the code fragment below?

int[] nums = new int[100]; for (int i = 0; i < nums.length; i++) { // INSERT STATEMENT HERE }

nums[i] = i+1; Signup and view all the answers

What is the correct way to initialize an array in Java?

a.array = 1; Signup and view all the answers

In the given code, what would be the output of System.out.print(values); System.out.print(" " + numbers);?

[0, 2, 4, 6, 8] [0, 2, 4, 6, 8] Signup and view all the answers

What does the statement 'a.numbers[k] = k + 1;' inside the for loop in the given code segment do?

It assigns the value of k+1 to numbers array element at index k. Signup and view all the answers

What is the purpose of the following code segment: 'System.out.println(number);'?

It prints the value of 'number' in the console. Signup and view all the answers

What would be the output of the following code segment: 'System.out.print(count);'?

4 Signup and view all the answers

Assuming 'values' is an array of integer values, what does the condition 'values[k] % 2 == 0' in a for loop check for?

Check if the element at index k in 'values' is divisible by 2. Signup and view all the answers

Study Notes

Array Declaration and Initialization

To create an array with 20 double elements, use double[] array = new double[20];
The correct syntax for declaring and initializing an array is int[] array = {4, 3, 5, 2, 0};

Array Element Access

The value of array in the declaration int[] array = {4, 3, 5, 2, 0}; is 4 at index 0, 3 at index 1, 5 at index 2, 2 at index 3, and 0 at index 4.
Accessing an array element out of bounds causes a runtime error.

Looping and Array Initialization

The code segment int[] values = new int[10]; for (int k = 0; k < values.length; k++) { values[k] = k * 2; } initializes an array with values 0, 2, 4, ..., 18.
The missing statement in the code fragment int[] numbers = new int[100]; for (int k = 0; k < numbers.length; k++) { ________________________ } is numbers[k] = k + 1;

Array Variables and Enhanced for Loop

The code segment int[] values = { 1, 3, 1, 3, 1 }; int[] numbers = values; for (int k = 0; k < values.length; k++) { values[k] = k * 2; } outputs 0 2 4 6 8 for values and 0 2 4 6 8 for numbers.
The enhanced for loop int[] values = { 1, 3, 5, 3, 7 }; int count = 0; for (int number : values) { if (number > 4) { count++; } } outputs 2 for count.
The most appropriate statement for the body of an enhanced for loop is System.out.println(number);

Array Algorithm

The purpose of the code segment int count = 0; for (int k = 0; k < values.length; k++) { if (values[k] % 2 == 0) { System.out.println(number); } } is to count the number of even values in the array values.

Java Arrays Declaration and Initialization Practice