Arrays in java introduction

Lecture 44:- Arrays in java introduction

In Java, an array is a data structure that allows you to store a fixed-size collection of elements of the same data type. Arrays provide a convenient way to group multiple related values under a single variable name and access them using an index. The index starts from 0 and goes up to the size of the array minus one.

To use arrays in Java, you need to declare the array variable and initialize it with the desired number of elements. Here's the basic syntax to declare and initialize an array in Java:

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dataType[] arrayName = new dataType[arraySize];

• dataType: The data type of the elements to be stored in the array.
• arrayName: The name of the array variable.
• arraySize: The number of elements the array can hold.

Once you have created an array, you can access and modify individual elements using their index. Array indices start from 0, so the first element is accessed using index 0, the second element with index 1, and so on.

Here's an example of how to declare, initialize, and use an array of integers in Java:

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public class ArrayExample {    public static void main(String[] args) {        // Declare and initialize an array of integers        int[] numbers = new int[5];        // Assign values to the array elements        numbers[0] = 10;        numbers[1] = 20;        numbers[2] = 30;        numbers[3] = 40;        numbers[4] = 50;        // Access and print array elements        System.out.println("First element: " + numbers[0]);        System.out.println("Second element: " + numbers[1]);        System.out.println("Third element: " + numbers[2]);        // Modify an array element        numbers[3] = 45;        // Calculate the sum of all elements        int sum = 0;        for (int i = 0; i < numbers.length; i++) {            sum += numbers[i];        }        System.out.println("Sum of all elements: " + sum);    } }

Output:

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First element: 10 Second element: 20 Third element: 30 Sum of all elements: 155

In the example above, we declare an array of integers named numbers with a size of 5. We then assign values to each element using the index. We access and print individual elements using their respective indices. We also modify one of the elements by updating its value. Finally, we calculate the sum of all elements using a for loop that iterates through the array.

Arrays are a fundamental concept in Java and are used extensively in various applications to store and manipulate collections of data efficiently.