Insert Element at the End of an Array (original) (raw)

Last Updated : 07 Nov, 2024

Given an array of integers, the task is to insert an element at the end of the array.

**Examples:

**Input: arr[] = [10, 20, 30, 40], ele = 50
**Output: [10, 20, 30, 40, 50]

**Input: arr[] = [], ele = 20
**Output: [20]

Table of Content

[Approach 1] Using Built-In Methods

We will use library methods like **push_back() in C++, **add() in Java and C#, **append() in Python and **push() in JavaScript.

C++ `

// C++ program to insert given element at the end // of an array using built-in methods

#include #include using namespace std;

int main() { vector arr = {10, 20, 30, 40}; int ele = 50; cout << "Array before insertion\n"; for (int i = 0; i < arr.size(); i++) cout << arr[i] << " ";

  // Insert element at the end
arr.push_back(ele);

cout << "\nArray after insertion\n";
for (int i = 0; i < arr.size(); i++)
    cout << arr[i] << " ";

return 0;

}

Java

// Java program to insert a given element at the end of an array // using built-in methods

import java.util.ArrayList; import java.util.Arrays;

class GfG { public static void main(String[] args) { ArrayList arr = new ArrayList<>(Arrays.asList(10, 20, 30, 40)); int ele = 50; System.out.println("Array before insertion"); for (int i = 0; i < arr.size(); i++) System.out.print(arr.get(i) + " ");

    // Insert element at the end
    arr.add(ele);

    System.out.println("\nArray after insertion");
    for (int i = 0; i < arr.size(); i++)
        System.out.print(arr.get(i) + " ");
}

}

Python

Python program to insert a given element at the end

of an array using built-in methods

if name == "main": arr = [10, 20, 30, 40] ele = 50 print("Array before insertion") for i in range(len(arr)): print(arr[i], end=" ")

# Insert element at the end
arr.append(ele)

print("\nArray after insertion")
for i in range(len(arr)):
    print(arr[i], end=" ")

C#

// C# program to insert a given element at the end // of an array using built-in methods

using System; using System.Collections.Generic;

class GfG { static void Main() { List arr = new List { 10, 20, 30, 40 }; int ele = 50; Console.WriteLine("Array before insertion"); foreach (int num in arr) Console.Write(num + " ");

    // Insert element at the end
    arr.Add(ele);

    Console.WriteLine("\nArray after insertion");
    foreach (int num in arr)
        Console.Write(num + " ");
}

}

JavaScript

// JavaScript program to insert a given element at the end // of an array using built-in methods

let arr = [10, 20, 30, 40]; let ele = 50; console.log("Array before insertion"); console.log(arr.join(" "));

// Insert element at the end arr.push(ele);

console.log("Array after insertion"); console.log(arr.join(" "));

`

Output

Array before insertion 10 20 30 40 Array after insertion 10 20 30 40 50

**Time Complexity: O(1)
**Auxiliary Space: O(1)

[Approach 2] Using Custom Method

To insert an element at the end of an array, we can simply add the new element at the nth index.

C++ `

// C++ program to insert given element at the end // of an array using custom methods

#include #include using namespace std;

int main() { int n = 4; vector arr = {10, 20, 30, 40, 0}; int ele = 50; cout << "Array before insertion\n"; for (int i = 0; i < n; i++) cout << arr[i] << " ";

  arr[n] = ele;

cout << "\nArray after insertion\n";
for (int i = 0; i <= n; i++)
    cout << arr[i] << " ";

return 0;

}

C

// C program to insert given element at the end // of an array using custom methods

#include <stdio.h>

int main() { int n = 4; int arr[5] = {10, 20, 30, 40, 0}; int ele = 50;

printf("Array before insertion\n");
for (int i = 0; i < n; i++) {
    printf("%d ", arr[i]);
}

// Inserting element at the end of the array
arr[n] = ele;

printf("\nArray after insertion\n");
for (int i = 0; i <= n; i++) {
    printf("%d ", arr[i]);
}

return 0;

}

Java

// Java program to insert given element at the end // of an array using custom methods

class GfG { public static void main(String[] args) { int n = 4; int[] arr = {10, 20, 30, 40, 0}; int ele = 50;

    System.out.println("Array before insertion");
    for (int i = 0; i < n; i++) {
        System.out.print(arr[i] + " ");
    }

    // Inserting element at the end of the array
    arr[n] = ele;

    System.out.println("\nArray after insertion");
    for (int i = 0; i <= n; i++) {
        System.out.print(arr[i] + " ");
    }
}

}

Python

Python program to insert given element at the end

of an array using custom methods

if name == "main": n = 4 arr = [10, 20, 30, 40, 0] ele = 50

print("Array before insertion")
for i in range(n):
    print(arr[i], end=" ")

# Inserting element at the end of the array
arr[n] = ele

print("\nArray after insertion")
for i in range(n + 1):
    print(arr[i], end=" ")

C#

using System;

class GfG { static void Main() { int n = 4; int[] arr = { 10, 20, 30, 40, 0 }; int ele = 50;

    Console.WriteLine("Array before insertion");
    for (int i = 0; i < n; i++) {
        Console.Write(arr[i] + " ");
    }

    // Inserting element at the end of the array
    arr[n] = ele;

    Console.WriteLine("\nArray after insertion");
    for (int i = 0; i <= n; i++) {
        Console.Write(arr[i] + " ");
    }
}

}

JavaScript

// JavaScript program to insert given element at the end // of an array using custom methods

let n = 4; let arr = [10, 20, 30, 40, 0]; let ele = 50;

console.log("Array before insertion"); console.log(arr.slice(0, n).join(" "));

// Inserting element at the end of the array arr[n] = ele;

console.log("Array after insertion"); console.log(arr.join(" "));

`

Output

Array before insertion 10 20 30 40 Array after insertion 10 20 30 40 50

**Time Complexity: O(1)
**Auxiliary Space: O(1)