Sum of array elements using recursion
Given an array of integers, find sum of array elements using recursion.
Examples:
Input : A[] = {1, 2, 3} Output : 6 1 + 2 + 3 = 6 Input : A[] = {15, 12, 13, 10} Output : 50
We have discussed iterative solution in below post.
Sum of elements in a given array
In this post, recursive solution is discussed.
C++
// C++ program to find sum of array // elements using recursion. #include <stdio.h> // Return sum of elements in A[0..N-1] // using recursion. int findSum( int A[], int N) { if (N <= 0) return 0; return (findSum(A, N - 1) + A[N - 1]); } // Driver code int main() { int A[] = { 1, 2, 3, 4, 5 }; int N = sizeof (A) / sizeof (A[0]); printf ( "%d" , findSum(A, N)); return 0; } |
Java
// Java program to find sum of array // elements using recursion. public class Test { static int arr[] = { 1 , 2 , 3 , 4 , 5 }; // Return sum of elements in A[0..N-1] // using recursion. static int findSum( int A[], int N) { if (N <= 0 ) return 0 ; return (findSum(A, N - 1 ) + A[N - 1 ]); } // Driver method public static void main(String[] args) { System.out.println(findSum(arr, arr.length)); } } |
Python3
# Python program to find sum of array # elements using recursion. # Return sum of elements in A[0..N-1] # using recursion. def _findSum(arr, N): if N < = 0 : return 0 else : return _findSum(arr, N - 1 ) + arr[N - 1 ] # driver code arr = [] # input values to list arr = [ 1 , 2 , 3 , 4 , 5 ] # calculating length of array N = len (arr) ans = _findSum(arr,N) print (ans) # This code is contributed by Khare Ishita |
C#
// C# program to find sum of array // elements using recursion. using System; class Test { static int []arr = {1, 2, 3, 4, 5}; // Return sum of elements in // A[0..N-1] using recursion. static int findSum( int []A, int N) { if (N <= 0) return 0; return (findSum(A, N - 1) + A[N - 1]); } // Driver Code public static void Main() { Console.Write(findSum(arr, arr.Length)); } } // This code is contributed by Nitin Mittal. |
PHP
<?php // PHP program to find sum // of array elements using // recursion. // Return sum of elements // in A[0..N-1] using recursion. function findSum( $A , $N ) { if ( $N <= 0) return 0; return (findSum( $A , $N - 1) + $A [ $N - 1]); } // Driver code $A = array (1, 2, 3, 4, 5); $N = sizeof( $A ); echo findSum( $A , $N ); // This code is contributed // by ihritik ?> |
Javascript
<script> // JavaScript program to find sum of array // elements using recursion. // Return sum of elements in A[0..N-1] // using recursion. function findSum(A, N) { if (N <= 0) return 0; return (findSum(A, N - 1) + A[N - 1]); } // Driver code let A = [1, 2, 3, 4, 5]; let N = A.length; document.write(findSum(A, N)); </script> |
Output
15
Time Complexity; O(n)
Here n is the number of elements in the array.
Auxiliary Space: O(n)
The extra space is used in recursion call stack.
How does above recursive solution work?
This article is contributed by
Prakhar Agrawal.
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