Generate an Array by multiplying each element of given Array by K - GeeksforGeeks

19 Jan, 2022
Given an array arr[] of size N and an integer K. The task is to multiply each element of the array by K.
Examples :
Input: arr[] = { 3, 4 }, K = 2Output: 6 8Explanation: The elements become 3*2 = 6 and 4*2 = 8.
Input: arr[] = { 0, 1, 2 }, K = 7Output: { 0, 7, 14 }
Approach: The given problem can be solved using the following steps :
Iterate through all the elements in the list
Multiply each element by K
Returned the modified list
Below is the implementation of the above approach.
C++
Java
Python
C#
Javascript
// C++ code for the above approach#include <bits/stdc++.h>using namespace std; // Function to multiply all// the elements of array by Kvoid multiplyAllByK(vector<int> arr, int K){    int N = arr.size();     // Loop to multiply all    // the array elements    for (int i = 0; i < N; i++) {        int x = arr[i];        arr[i] = K * x;    }     // Print the modified array    for (int i = 0; i < N; i++)        cout << (arr[i]) << " ";} // Driver codeint main(){     vector<int> arr;    arr.push_back(3);    arr.push_back(4);    int K = 2;    multiplyAllByK(arr, K);    return 0;} // This code is contributed by lokeshpotta20.
// Java code to implement above approachimport java.io.*;import java.util.*; class GFG {     // Function to multiply all    // the elements of array by K    public static void multiplyAllByK(        ArrayList<Integer> arr, int K)    {        int N = arr.size();         // Loop to multiply all        // the array elements        for (int i = 0; i < N; i++) {            int x = arr.get(i);            arr.set(i, K * x);        }         // Print the modified array        for (int i = 0; i < N; i++)            System.out.print(arr.get(i) + " ");    }     // Driver code    public static void main(String[] args)    {        ArrayList<Integer> arr = new ArrayList<Integer>();        arr.add(3);        arr.add(4);        int K = 2;        multiplyAllByK(arr, K);    }}
# Python code to implement above approach # Function to multiply all# the elements of array by Kdef multiplyAllByK(arr, K):         n = len(arr)         for i in range(n):        x = arr[i]        arr[i] = K * x             for i in range(n):        print(arr[i], end = ' ') # Driver codearr = [3, 4]K = 2multiplyAllByK(arr, K) # This code is contributed by Samim Hossain Mondal.
// C# code to implement above approach using System;using System.Collections.Generic; public class GFG {     // Function to multiply all    // the elements of array by K    public static void multiplyAllByK(        List<int> arr, int K)    {        int N = arr.Count;         // Loop to multiply all        // the array elements        for (int i = 0; i < N; i++) {            int x = arr[i];            arr[i] =( K * x);        }         // Print the modified array        for (int i = 0; i < N; i++)            Console.Write(arr[i] + " ");    }     // Driver code    public static void Main(String[] args)    {        List<int> arr = new List<int>();        arr.Add(3);        arr.Add(4);        int K = 2;        multiplyAllByK(arr, K);    }} // This code is contributed by 29AjayKumar
<script>    // JavaScript code for the above approach     // Function to multiply all    // the elements of array by K    const multiplyAllByK = (arr, K) => {        let N = arr.length;         // Loop to multiply all        // the array elements        for (let i = 0; i < N; i++) {            let x = arr[i];            arr[i] = K * x;        }         // Print the modified array        for (let i = 0; i < N; i++)            document.write(`${arr[i]} `);    }     // Driver code    let arr = [];    arr.push(3);    arr.push(4);    let K = 2;    multiplyAllByK(arr, K); // This code is contributed by rakeshsahni </script>
6 8 
Time Complexity: O(N)Auxiliary Space: O(1)
Approach Using Lambda Expression: This can also be implemented using lambda expression. 
n -> n * K where n can be a particular element, or complete array.
Below is the implementation of the above approach:
C++
C
Java
Python3
C#
Javascript
// C++ code to implement above approach#include <iostream>using namespace std; // Function to multiply all// the elements of array by Kvoid multiplyAllByK(int arr[], int K){  for(int i = 0; i < 2; i++)    arr[i] *= K;  for (int i = 0; i < 2; i++)    cout << arr[i] << " ";} // Driver codeint main(){  int arr[2];  arr[0] = 3;  arr[1] = 4;  int K = 2;  multiplyAllByK(arr, K);   return 0;} // This code is contributed by Shubham Singh
// C code to implement above approach#include <stdio.h> // Function to multiply all// the elements of array by Kvoid multiplyAllByK(int arr[], int K){    for(int i = 0; i < 2; i++) arr[i] *= K;    for (int i = 0; i<2; i++)        printf("%d ",arr[i]);} // Driver codeint main(){    int arr[2];    arr[0] = 3;    arr[1] = 4;    int K = 2;    multiplyAllByK(arr, K);         return 0;} //This code is contributed by Shubham Singh
// Java code to implement above approachimport java.io.*;import java.util.*; class GFG {     // Function to multiply all    // the elements of array by K    public static void multiplyAllByK(        ArrayList<Integer> arr, int K)    {        arr.replaceAll(n -> n * K);        for (Integer x : arr)            System.out.print(x + " ");    }     // Driver code    public static void main(String[] args)    {        ArrayList<Integer> arr            = new ArrayList<Integer>();        arr.add(3);        arr.add(4);        int K = 2;        multiplyAllByK(arr, K);    }}
# Python3 code to implement above approach # Function to multiply all# the elements of array by Kdef multiplyAllByK(arr, K):             lambda_func = lambda n: n * K    for i in range(len(arr)):        print(lambda_func(arr[i]), end = ' ') # Driver codearr = [3, 4]K = 2 multiplyAllByK(arr, K) # This code is contributed by Samim Hossain Mondal.
// C# code to implement above approachusing System;using System.Collections.Generic;using System.Linq; public class GFG {     // Function to multiply all    // the elements of array by K    public static void multiplyAllByK(        List<int> arr, int K)    {        var temp = arr.Select(n => n * K);        foreach (int x in temp)            Console.Write(x + " ");    }     // Driver code    public static void Main(String[] args)    {        List<int> arr            = new List<int>();        arr.Add(3);        arr.Add(4);        int K = 2;        multiplyAllByK(arr, K);    }} // This code is contributed by shikhasingrajput
<script>// Javascript code to implement above approach // Function to multiply all// the elements of array by Kfunction multiplyAllByK(arr, K) {    arr = arr.map(k => {        return k * K    });    for (x of arr)        document.write(x + " ");} // Driver codelet arr = [];arr.push(3);arr.push(4);let K = 2;multiplyAllByK(arr, K); // This code is contributed by saurabh_jaiswal.</script>
6 8 
 Time Complexity: O(N)Auxiliary Space: O(1) 
lokeshpotta20
29AjayKumar
samim2000
rakeshsahni
shikhasingrajput
_saurabh_jaiswal
shubhamsingh84100
SHUBHAMSINGH10
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