Lesson 2

Question 1

Are used to store multiple values in a single variable, instead of declaring
separate variables for each value.

Answer 1

Arrays

Question 2

Advantages of Array

Answer 2

•Code Optimization
•Random access

Question 3

Disadvantages of Array

Answer 3

Size Limit

Question 4

Types of Array in java

Answer 4

•Single Dimensional Array
•Multidimensional Array

Question 5

Array Declaration

Answer 5

dataType[] arrayRefVar;
//preferredway.
or
dataType arrayRefVar[];
// works but not preferred way.

Question 6

Example of Declaration of array

Answer 6

double[] myList; // preferred way.
or
double myList[]; // works but not preferred way.

Question 7

Array Initialization example

Answer 7

// declare an array
int[] age = new int[5];
// initialize array
age[0] = 12;
age[1] = 4;
age[2] = 5;

Question 8

Example: Access Array Elements

Answer 8

class Main {
public static void main(String[] args) {
// create an array
int[] age = {12, 4, 5, 2, 5};
// access each array elements
System.out.println(“Accessing Elements of Array:”);
System.out.println(“First Element: “ + age[0]);
System.out.println(“Second Element: “ + age[1]);
System.out.println(“Third Element: “ + age[2]);
System.out.println(“Fourth Element: “ + age[3]);
System.out.println(“Fifth Element: “ + age[4]);
}
}

Question 9

Example: Using For Loop
Output:
12
4
5

Answer 9

class Main {
public static void main(String[] args) {
// create an array
int[] age = {12, 4, 5};
// loop through the array
// using for loop
System.out.println(“Using for Loop:”);
for(int i = 0; i < age.length; i++) {
System.out.println(age[i]);
} } }

Question 10

Example: Using the for-each Loop
Output:
12
4
5

Answer 10

Output class Main {
public static void main(String[] args) {
// create an array
int[] age = {12, 4, 5};
// loop through the array
// using for loop
System.out.println(“Using for-each Loop:”);
for(int a : age) {
System.out.println(a);
} } }

Question 11

Creating Array
Syntax

Answer 11

arrayRefVar = new dataType[arraySize];

dataType[] arrayRefVar = new dataType[arraySize];
Alternatively you can create arrays as follows −
dataType[] arrayRefVar = {value0, value1, …, valuek};

Question 12

Processing Arrays
The foreach Loops
Example:

Answer 12

public class TestArray {
public static void main(String[] args) {
double[] myList = {1.9, 2.9, 3.4, 3.5};
// Print all the array elements
for (double element: myList) {
System.out.println(element);
} } }