How to modify two array elements in Java

An array is a linear data structure in which elements are stored in contiguous memory locations.

According to the problem statement, we have to change two array elements with each other. In other words, changing two array elements can also be called swapping or swapping two elements

Let’s explore this article and see how it can be done using the Java programming language.

Show you some examples

Example 1

Suppose we have the following array = [10, 2, 3, -5, 99, 12, 0, -1]

Now if we swap the 5th and 8th elements,

Then, we got the new array [10, 2, 3, -5, -1, 12, 0, 99]

Example 2

Suppose we have the following array = [55, 10, 29, 74, 12, 45, 6, 5, 269]

Now if we swap the fourth and eighth elements

Then, we got the new array [55, 10, 29, 5, 12, 45, 6, 74, 269]

Example 3

Suppose we have the following array = [556, 10, 259, 874, 123, 453, -96, -54, -2369]

Now if we swap the second and sixth elements

Then, we got the new array [556, 453, 259, 874, 123, 10, -96, -54, -2369]

algorithm

Algorithm 1 (by using the third variable)

• Step 1 - After storing the array, take two indices to swap the elements.

• Step 2 - Store the first element in a temporary variable.

• Step 3 - Now store the second element value in the first element

• Step 4 - Finally store the temporary variable value in the second element.

• Step 5 - Print the array elements.

Algorithm 2 (without using the third variable)

• Step 1 - After storing the array, take two indices to swap the elements.

• Step 2 - Add the first and second elements and store them in the first element.

• Step 3 - Subtract the second element from the first element and store it in the second element.

• Step 4 - Again subtract the second element from the first element and store it in the first element.

• Step 5 - Print the array elements.

grammar

To get the length of an array (the number of elements in the array), arrays have a built-in property, length.

The following is its syntax -

array.length

Among them, "array" refers to the array reference.

You can use the Arrays.sort() method to sort an array in ascending order.

Arrays.sort(array_name);

Multiple methods

We provide solutions in different ways.

• Use a third variable to change two array elements.

• Change two array elements without using a third variable.

Let’s look at the program and its output one by one.

Method 1: Use the third variable

In this method, we change the array element by using another variable that temporarily holds the value of an element.

Example

import java.io.*;
import java.util.Arrays;
public class Main {
   public static void main(String[] args) {
      
      // The array elements
      int arr[] = { 10, 2, 3, -5, 99, 12, 0, -1 };
      
      // Print all array elements
      System.out.println("The array elements before swapping are-");
      for (int i : arr) {
         System.out.print(i + " ");
      }
      
      // We will be swapping 2nd index element with 4th index element
      int firstIndex = 2, secondIndex = 4;
      
      // Temp variable
      int temp = arr[firstIndex];
      
      // Swapping
      arr[firstIndex] = arr[secondIndex];
      arr[secondIndex] = temp;
      
      // Print all array elements
      System.out.println("\nThe array elements after swapping are-");
      for (int i : arr) {
         System.out.print(i + " ");
      }
   }
}

Output

The array elements before swapping are-
10 2 3 -5 99 12 0 -1 
The array elements after swapping are-
10 2 99 -5 3 12 0 -1 

Method 2: Do not use the third variable

In this method, unlike the previous method, we can change the array elements without using other variables.

Example

import java.io.*;
import java.util.Arrays;
public class Main {
   public static void main(String[] args) {
      // The array elements
      int arr[] = { 10, 2, 3, -5, 99, 12, 0, -1 };
      
      // Print all array elements
      System.out.println("The array elements before swapping are-");
      for (int i : arr) {
         System.out.print(i + " ");
      }
      
      // We will be swapping 2nd index element with 4th index element
      int firstIndex = 2, secondIndex = 4;
      
      // Swapping array elements
      arr[firstIndex] = arr[firstIndex] + arr[secondIndex];
      arr[secondIndex] = arr[firstIndex] - arr[secondIndex];
      arr[firstIndex] = arr[firstIndex] - arr[secondIndex];
      
      // Print all array elements
      System.out.println("\nThe array elements after swapping are-");
      for (int i : arr) {
         System.out.print(i + " ");
      }
   }
}

Output

The array elements before swapping are-
10 2 3 -5 99 12 0 -1 
The array elements after swapping are-
10 2 99 -5 3 12 0 -1 

In this article, we explored how to change two array elements using the Java programming language.

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