How to Insert an element at a specific position in an Array in Java
Last Updated :
12 Mar, 2024
An array is a collection of items stored at contiguous memory locations. In this article, we will see how to insert an element in an array in Java.
Given an array arr of size n, this article tells how to insert an element x in this array arr at a specific position pos.
Approach 1:Â
Here’s how to do it.
- First get the element to be inserted, say x.
- Then get the position at which this element is to be inserted, say pos.
- Create a new array with the size one greater than the previous size.
- Copy all the elements from previous array into the new array till the position pos.
- Insert the element x at position pos.
- Insert the rest of the elements from the previous array into the new array after the pos.
Below is the implementation of the above approach:
Java// Java Program to Insert an element
// at a specific position in an Array
import java.io.*;
import java.lang.*;
import java.util.*;
class GFG {
// Function to insert x in arr at position pos
public static int[] insertX(int n, int arr[],
int x, int pos)
{
int i;
// create a new array of size n+1
int newarr[] = new int[n + 1];
// insert the elements from
// the old array into the new array
// insert all elements till pos
// then insert x at pos
// then insert rest of the elements
for (i = 0; i < n + 1; i++) {
if (i < pos - 1)
newarr[i] = arr[i];
else if (i == pos - 1)
newarr[i] = x;
else
newarr[i] = arr[i - 1];
}
return newarr;
}
// Driver code
public static void main(String[] args)
{
int n = 10;
int i;
// initial array of size 10
int arr[]
= { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
// print the original array
System.out.println("Initial Array:\n"
+ Arrays.toString(arr));
// element to be inserted
int x = 50;
// position at which element
// is to be inserted
int pos = 5;
// call the method to insert x
// in arr at position pos
arr = insertX(n, arr, x, pos);
// print the updated array
System.out.println("\nArray with " + x
+ " inserted at position "
+ pos + ":\n"
+ Arrays.toString(arr));
}
}
OutputInitial Array:
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
Array with 50 inserted at position 5:
[1, 2, 3, 4, 50, 5, 6, 7, 8, 9, 10]
Approach 2:Â
Here’s how to do it.
- First get the element to be inserted, say element.
- Then get the position at which this element is to be inserted, say position.
- Convert array to ArrayList.
- Add element at position using list.add(position, element).
- Convert ArrayList back to array and print.
Below is the implementation of the above approach:
Java// Java Program to Insert an element
// at a specific position in an Array
// using ArrayList
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class AddElementAtPositionInArray {
// Method to add element at position
private static void
addElement(Integer[] arr, int element, int position)
{
// Printing the original array
System.out.println("Initial Array:\n"
+ Arrays.toString(arr));
// Converting array to ArrayList
List<Integer> list
= new ArrayList<>(Arrays.asList(arr));
// Adding the element at position
list.add(position - 1, element);
// Converting the list back to array
arr = list.toArray(arr);
// Printing the updated array
System.out.println("\nArray with " + element
+ " inserted at position "
+ position + ":\n"
+ Arrays.toString(arr));
}
// Drivers Method
public static void main(String[] args)
{
// Sample array
Integer[] arr = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
// Element to be inserted
int element = 50;
// Position to insert
int position = 5;
// Calling the function to insert
addElement(arr, element, position);
}
}
OutputInitial Array:
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
Array with 50 inserted at position 5:
[1, 2, 3, 4, 50, 5, 6, 7, 8, 9, 10]
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