Last Updated : 08 Nov, 2024
Given an array of integers, the task is to delete an element from the beginning of the array.
Examples:
[Approach 1] Using Built-In MethodsInput: arr[] = [10, 20, 30, 40]
Output: [20, 30, 40]Input: arr[] = [20]
Output: []
We will use library methods like erase() in C++, remove() in Java, del in Python, removeAt() in C# and shift() in JavaScript.
C++
// C++ program to delete an element from the beginning
// of an array using built-in functions
#include <iostream>
#include <vector>
using namespace std;
int main() {
vector<int> arr = { 10, 20, 30, 40 };
cout << "Array before deletion\n";
for (int i = 0; i < arr.size(); i++)
cout << arr[i] << " ";
// Delete the first element using an iterator
// pointing to the beginning
arr.erase(arr.begin());
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 beginning
// of an array using built-in functions
import java.util.*;
class GfG {
public static void main(String[] args) {
ArrayList<Integer> arr = new ArrayList<>
(Arrays.asList(10, 20, 30, 40));
System.out.println("Array before deletion");
for (int i = 0; i < arr.size(); i++)
System.out.print(arr.get(i) + " ");
// Remove the first element
arr.remove(0);
System.out.println("\nArray after deletion");
for (int i = 0; i < arr.size(); i++)
System.out.print(arr.get(i) + " ");
}
}
Python
# Python program to delete an element from the
# beginning of a list using built-in functions
arr = [10, 20, 30, 40]
print("Array before deletion")
for i in range(len(arr)):
print(arr[i], end=" ")
# Remove the first element
del arr[0]
print("\nArray after deletion")
for i in range(len(arr)):
print(arr[i], end=" ")
C#
// C# program to delete an element from the beginning
// of a list
using System;
using System.Collections.Generic;
class GfG {
static void Main() {
List<int> arr = new List<int> { 10, 20, 30, 40 };
Console.WriteLine("Array before deletion");
for (int i = 0; i < arr.Count; i++)
Console.Write(arr[i] + " ");
// Remove the first element using
// the built-in RemoveAt method
arr.RemoveAt(0);
Console.WriteLine("\nArray after deletion");
for (int i = 0; i < arr.Count; i++)
Console.Write(arr[i] + " ");
}
}
JavaScript
// JavaScript program to delete an element
// from the beginning of an array
let arr = [10, 20, 30, 40];
console.log("Array before deletion");
console.log(arr);
// Remove the first element
arr.shift();
console.log("Array after deletion");
console.log(arr);
Array before deletion 10 20 30 40 Array after deletion 20 30 40
Time Complexity: O(n)
Auxiliary Space: O(1)
The idea is to start from the second element and shift all the elements one position to the left. After shifting all the elements, reduce the array size by 1 to remove the extra element at the end.
C++
// C++ program to delete an element from the beginning
// of an array using custom method
#include <iostream>
#include <vector>
using namespace std;
int main() {
vector<int> arr = { 10, 20, 30, 40 };
int n = arr.size();
cout << "Array before deletion\n";
for (int i = 0; i < n; i++)
cout << arr[i] << " ";
// Shift all the elements 1 position to the left
// starting from second element
for(int i = 1; i < n; i++)
arr[i - 1] = 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 beginning
// of an array using custom method
#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]);
// Shift all the elements 1 position to the left
// starting from second element
for (int i = 1; i < n; i++) {
arr[i - 1] = 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 beginning
// of an array using custom method
import java.util.Arrays;
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] + " ");
// Shift all the elements 1 position to the left
// starting from second element
for(int i = 1; i < n; i++)
arr[i - 1] = 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 beginning
# of an array using custom method
if __name__ == "__main__":
arr = [10, 20, 30, 40]
n = len(arr)
print("Array before deletion")
for i in range(n):
print(arr[i], end=" ")
# Shift all the elements 1 position to the left
# starting from second element
for i in range(1, n):
arr[i - 1] = arr[i]
# 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 beginning
// of an array using custom method
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] + " ");
// Shift all the elements 1 position to the left
// starting from second element
for (int i = 1; i < n; i++)
arr[i - 1] = 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
// beginning of an array using custom method
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]);
// Shift all the elements 1 position to the left
// starting from second element
for (let i = 1; i < n; i++) {
arr[i - 1] = arr[i];
}
// Reduce the array size by 1
n--;
console.log("Array after deletion");
for(let i = 0; i < n; i++)
console.log(arr[i]);
Array before deletion 10 20 30 40 Array after deletion 20 30 40
Time Complexity: O(n)
Auxiliary Space: O(1)
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