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.

 

C code
While loop in C

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 :

199

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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 :

199
While loop in C

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 :

199

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While loop in C