Delete an Element from the end of an array (original) (raw)

Last Updated : 08 Nov, 2024

Given an array of integers, the task is to delete an element from the **end of the array.

**Examples:

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

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

Table of Content

• [Approach 1] Using Built-In Methods
• [Approach 2] Using Custom Method

[Approach 1] Using Built-In Methods

We will use library methods like **pop_back() in C++, **remove() in Java, **pop() in Python and JavaScript and **removeAt() in C#.

C++ `

// C++ program to delete an element from the end // of an array using in-built methods

#include #include using namespace std;

int main() { vector arr = { 10, 20, 30, 40 };

cout << "Array before deletion\n";
for (int i = 0; i < arr.size(); i++)
    cout << arr[i] << " ";
  
// Remove the last element from the array
arr.pop_back();

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

return 0;

}

Java

// Java program to delete an element from the end of an array // using in-built methods

import java.util.*;

class GfG { public static void main(String[] args) { ArrayList arr = new ArrayList<> (Arrays.asList(10, 20, 30, 40));

    System.out.println("Array before deletion");
    for (int ele : arr) 
        System.out.print(ele + " ");

    // Remove the last element from the array
    arr.remove(arr.size() - 1);

    System.out.println("\nArray after deletion");
    for (int ele : arr) 
        System.out.print(ele + " ");
}

}

Python

Python program to delete an element from the end

of an array using in-built methods

arr = [10, 20, 30, 40]

print("Array before deletion") for ele in arr: print(ele, end=" ")

Remove the last element from the array

arr.pop()

print("\nArray after deletion") for ele in arr: print(ele, end=" ")

C#

// C# program to delete an element from the end // of an array using in-built methods

using System; using System.Collections.Generic;

class GfG { static void Main() { List arr = new List { 10, 20, 30, 40 };

    Console.WriteLine("Array before deletion");
    foreach (var ele in arr) 
        Console.Write(ele + " ");

    // Remove the last element from the array
    arr.RemoveAt(arr.Count - 1);

    Console.WriteLine("\nArray after deletion");
    foreach (var ele in arr) 
        Console.Write(ele + " ");
}

}

JavaScript

// JavaScript program to delete an element from the end // of an array using in-built methods

let arr = [10, 20, 30, 40];

console.log("Array before deletion"); console.log(arr);

// Remove the last element from the array arr.pop();

console.log("Array after deletion"); console.log(arr);

`

Output

Array before deletion 10 20 30 40 Array after deletion 10 20 30

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

[Approach 2] Using Custom Method

To delete an element from the end of an array, we can simply reduce the size of array by 1.

C++ `

// C++ program to delete an element from the end // of an array using custom methods

#include #include using namespace std;

int main() { vector arr = { 10, 20, 30, 40 }; int n = arr.size();

cout << "Array before deletion\n";
for (int i = 0; i < n; i++)
    cout << arr[i] << " ";
  
// Reduce the array size by 1
n--;

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

return 0;

}

C

// C program to delete an element from the end // of an array using custom methods

#include <stdio.h>

int main() { int arr[] = { 10, 20, 30, 40 }; int n = sizeof(arr)/sizeof(arr[0]);

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

// Reduce the array size by 1
n--;

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

return 0;

}

Java

// Java program to delete an element from the end // of an array using custom methods

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

    System.out.println("Array before deletion");
    for (int i = 0; i < n; i++)
        System.out.print(arr[i] + " ");
    
    // Reduce the array size by 1
    n--;

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

}

Python

Python program to delete an element from the end

of an array using custom methods

if name == "main": arr = [10, 20, 30, 40] n = len(arr)

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

# Reduce the array size by 1
n -= 1

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

C#

// C# program to delete an element from the end // of an array using custom methods

using System;

class GfG { static void Main() { int[] arr = { 10, 20, 30, 40 }; int n = arr.Length;

    Console.WriteLine("Array before deletion");
    for (int i = 0; i < n; i++)
        Console.Write(arr[i] + " ");
    
    // Reduce the array size by 1
    n--;

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

}

JavaScript

// JavaScript program to delete an element from the end // of an array using custom methods

let arr = [ 10, 20, 30, 40 ]; let n = arr.length;

console.log("Array before deletion"); for (let i = 0; i < n; i++) { console.log(arr[i]); }

// Reduce the array size by 1 n--;

console.log("\nArray after deletion"); for (let i = 0; i < n; i++) { console.log(arr[i]); }

`

Output

Array before deletion 10 20 30 40 Array after deletion 10 20 30

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