Modified version of summing an array with recursion in JavaScript
Let’s say, we are required to write a recursive function that sums all the elements of an array of
Numbers but with a twist and the twist is that the recursive function we write cannot initialize any
extra variable (memory).
Like we cannot use a variable to store the sum or to keep a count of the index of the array, it all
has to be using what we already have.
Here’s the solution −
We already have an array and can use its first element (i.e., the element at zeroth index to hold
the recursive sum).
The approach is that we repeatedly pop one element from the array and add it to the first
element of the array until we are left with only one element.
When we are left with only one element, it will be the cumulative sum of the array and we return
that. The code for this approach will be −
Example
const recursiveSum = arr => {
if(arr.length > 1){
arr[0] += arr.pop();
return recursiveSum(arr);
};
return arr[0];
};
console.log(recursiveSum([1,2,3,4]));
console.log(recursiveSum([1,2,3,4,3,6,3,32,7,9,5]));
console.log(recursiveSum([]));Output
The output in the console will be −
10
75
undefined
Published on 28-Aug-2020 17:31:37
