Replace every element of the array by its next element

Given an array arr, the task is to replace each element of the array with the element that appears after it and replace the last element with -1.

Examples:

Input: arr[] = {5, 1, 3, 2, 4} 
Output: 1 3 2 4 -1

Input: arr[] = {6, 8, 32, 12, 14, 10, 25 } 
Output: 8 32 12 14 10 25 -1 

Approach: Traverse the array from 0 to n-2 and update arr[i] = arr[i+1]. In the end set a[n-1] = -1 and print the contents of the updated array.

Below is the implementation of the above approach: 

C++

// C++ program to replace every element of the array
// with the element that appears after it
#include <bits/stdc++.h>
using namespace std;

// Function to print the array after replacing every element
// of the array with the element that appears after it
void updateArray(int arr[], int n)
{
    // Update array
    for (int i = 0; i <= n - 2; i++)
        arr[i] = arr[i + 1];

    // Change the last element to -1
    arr[n - 1] = -1;

    // Print the updated array
    for (int i = 0; i < n; i++)
        cout << arr[i] << " ";
}

// Driver program
int main()
{
    int arr[] = { 5, 1, 3, 2, 4 };
    int N = sizeof(arr) / sizeof(arr[0]);
    updateArray(arr, N);
    return 0;
}

Java

// Java program to replace every element
// of the array with the element that
// appears after it
class GFG
{

// Function to print the array after
// replacing every element of the array
// with the element that appears after it
static void updateArray(int arr[], int n)
{
    // Update array
    for (int i = 0; i <= n - 2; i++)
        arr[i] = arr[i + 1];

    // Change the last element to -1
    arr[n - 1] = -1;

    // Print the updated array
    for (int i = 0; i < n; i++)
        System.out.print(arr[i] + " ");
}

// Driver Code
public static void main(String []args)
{
    int arr[] = { 5, 1, 3, 2, 4 } ;
    int N = arr.length ;
    updateArray(arr, N);
}
}

// This code is contributed by Ryuga

Python3

# Python3 program to replace every
# element of the array with the
# element that appears after it

# Function to print the array after
# replacing every element of the
# array with the element that appears
# after it
def updateArray(arr, n):

    # Update array
    for i in range (n - 1):
        arr[i] = arr[i + 1]

    # Change the last element to -1
    arr[n - 1] = -1

    # Print the updated array
    for i in range( n):
        print (arr[i], end = " ")

# Driver Code
if __name__ == "__main__":

    arr = [ 5, 1, 3, 2, 4 ]
    N = len(arr)
    updateArray(arr, N)

# This code is contributed
# by ChitraNayal

C#

// C# program to replace every element
// of the array with the element that
// appears after it
using System;

class GFG
{

// Function to print the array after
// replacing every element of the array
// with the element that appears after it
static void updateArray(int[] arr, int n)
{
    // Update array
    for (int i = 0; i <= n - 2; i++)
        arr[i] = arr[i + 1];

    // Change the last element to -1
    arr[n - 1] = -1;

    // Print the updated array
    for (int i = 0; i < n; i++)
        Console.Write(arr[i] + " ");
}

// Driver Code
public static void Main()
{
    int[] arr = { 5, 1, 3, 2, 4 } ;
    int N = arr.Length ;
    updateArray(arr, N);
}
}

// This code is contributed
// by Akanksha Rai

PHP

<?php
// PHP program to replace every element
// of the array with the element that
// appears after it

// Function to print the array after
// replacing every element of the
// array with the element that appears
// after it
function updateArray(&$arr, $n)
{
    // Update array
    for ($i = 0; $i <= $n - 2; $i++)
        $arr[$i] = $arr[$i + 1];

    // Change the last element to -1
    $arr[$n - 1] = -1;

    // Print the updated array
    for ($i = 0; $i < $n; $i++)
    {
        echo ($arr[$i]);
        echo (" ");
    }
}

// Driver Code
$arr = array(5, 1, 3, 2, 4 );
$N = sizeof($arr);
updateArray($arr, $N);

// This code is contributed
// by Shivi_Aggarwal
?>

Javascript

<script>

// Javascript program to replace every element of the array
// with the element that appears after it

// Function to print the array after replacing every element
// of the array with the element that appears after it
function updateArray(arr, n)
{
    // Update array
    for (let i = 0; i <= n - 2; i++)
        arr[i] = arr[i + 1];

    // Change the last element to -1
    arr[n - 1] = -1;

    // Print the updated array
    for (let i = 0; i < n; i++)
        document.write(arr[i] + " ");
}

// Driver program

    let arr = [ 5, 1, 3, 2, 4 ];
    let N = arr.length;
    updateArray(arr, N);

//This code is contributed by Mayank Tyagi

</script>

C

// C program to replace every element of the array
// with the element that appears after it
#include <stdio.h>

// Function to print the array after replacing every element
// of the array with the element that appears after it
void updateArray(int arr[], int n)
{
    // Update array
    for (int i = 0; i <= n - 2; i++)
        arr[i] = arr[i + 1];

    // Change the last element to -1
    arr[n - 1] = -1;

    // Print the updated array
    for (int i = 0; i < n; i++)
        printf("%d ",arr[i]);
}

// Driver program
int main()
{
    int arr[] = { 5, 1, 3, 2, 4 };
    int N = sizeof(arr) / sizeof(arr[0]);
    updateArray(arr, N);
    return 0;
}

Output

1 3 2 4 -1 

Complexity Analysis:

• Time Complexity: O(n)
• Auxiliary Space: O(1)