How to Alter Two Array Elements in Java

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

As per problem statement, we have to alter two array elements with each other. Altering two array elements in other words can also be called swapping or exchanging two elements with each other

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

To Show you Some Instances

Instance-1

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

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

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

Instance-2

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

Now if we swap the 4th and 8th elements

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

Instance-3

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

Now if we swap the 2nd and 6th elements

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

Algorithm

Algorithm-1 (By Using a Third Variable)

• Step 1 − After storing the arrays, take two indices to swap elements.

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

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

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

• Step 5 − Print the array elements.

Algorithm-2 (Without Using a Third Variable)

• Step 1 − After storing the arrays, take two indices to swap elements.

• Step 2 − Add first and second element then store them in 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 in first element.

• Step 5 − Print the array elements.

Syntax

To get the length of an array (number of elements in that array), there is an inbuilt property of array i.e length.

Below refers to the syntax of it −

array.length

where, ‘array’ refers to the array reference.

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

Arrays.sort(array_name);

Multiple Approaches

We have provided the solution in different approaches.

• Altering Two Array Elements Using Third Variable.

• Altering Two Array Elements Without Using Third Variable.

Let’s see the program along with its output one by one.

Approach-1: By Using a Third variable

In this approach, we alter the array elements by using another variable that temporarily holds the value of one 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 

Approach-2: Without Using a Third Variable

In this approach, we alter the array elements without using another variable unlike the previous method.

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 alter two array elements with each other by using Java programming language.