Calculate the sum of elements in an array in C++

October 6, 2022

Program to calculate the sum of elements in an array in C++

Here, in this page we will discuss a C++ Program to find the sum of the elements of an array in C++ programming language we are given with an array and need to print the sum of elements of the given input array.

Here, in this page we will discuss the following methods to find the sum of the elements of the given input array.

Method 1 : Using Iteration
Method 2 : Top-down recursive approach
Method 3 : Bottom-up recursive approach.

Method 1 :

Declare a variable sum and initialize it to 0 i.e, sum=0
Run a loop from 0 to n,
Set sum = sum + arr[i]
After complete iteration print sum.

Method 1 : C++ Code

Run

#include<bits/stdc++.h>
using namespace std;

int main(){

   int arr[] = {10, 20, 30, 50, 89};

   int n = sizeof(arr)/sizeof(arr[0]); 

   int sum =0;

   for(int i=0; i<n; i++){
      sum += arr[i];
   }

   cout<<sum;
}

Output :

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Method 2 :

Create a recursive function say getSum(int arr[], int index, int len)
If(index==len-1) return arr[index]
Otherwise, return (arr[index] + getSum(arr, index+1, len))

Method 2 : C++ Code

Run

#include<bits/stdc++.h>
using namespace std;

//Recursive Function
int getSum(int arr[], int index, int len){

     if(index==len-1)
      return arr[index];

     return arr[index] + getSum(arr, index+1, len);
}
int main(){

   int arr[] = {10, 20, 30, 50, 89};

   int n = sizeof(arr)/sizeof(arr[0]); 

   cout<<getSum(arr, 0, n);
}

Output :

Method 3 :

Create a recursive function say getSum(int arr[], int index)
If(index==0) return arr[index]
Otherwise, return (arr[index] + getSum(arr, index-1))

Method 3 : C++ Code

Run

#include<bits/stdc++.h>
using namespace std;

//Recursive Function
int getSum(int arr[], int index){

   if(index==0)
     return arr[index];

   return arr[index] + getSum(arr, index-1);
}
int main(){

   int arr[] = {10, 20, 30, 50, 89};

   int n = sizeof(arr)/sizeof(arr[0]); 

   cout<<getSum(arr, n-1);
}

Output :

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