# How to find the sum of elements of a vector in C++ STL?

C++ STL | finding sum of the vector elements: Here, we are going to learn how to find the sum of the elements of a vector in C++ STL?
Submitted by IncludeHelp, on May 18, 2019

Given a vector and we have to find the sum of the elements using C++ program.

## Finding sum of vector elements

To find the sum of the elements, we can use accumulate() function which is defined in <numeric> header in C++ standard template library. It accepts the range of the iterators in which we have to find the sum of the elements; it also accepts a third parameter which can be used to provide an initial value of the sum.

Note: To use vector – include <vector> header, and to use sum() function – include <numeric> header or we can simply use <bits/stdc++.h> header file.

Syntax:

```    sum(iterator start, iterator end, initial_sum_value);
```

Here, start_position, iterator end_position are the iterators pointing to the start and end elements in a container to be reversed.
initial_sum_value – is an initial value of the sum that will be added to the result of the sum of the elements.

Example:

```    Input:
vector<int> v1{ 10, 20, 30, 40, 50};

sum(v1.begin(), v1.end(), 0);

Output:
150
```

### C++ STL program to find the sum of the vector elements

```//C++ STL program to find the sum of the vector elements
#include <iostream>
#include <numeric>
#include <vector>
using namespace std;

int main()
{
//vector
vector<int> v1{ 10, 20, 30, 40, 50 };

//printing elements
cout << "vector elements..." << endl;
for (int x : v1)
cout << x << " ";
cout << endl;

//finding sum with initial value of sum is 0
int sum = accumulate(v1.begin(), v1.end(), 0);
cout << "sum (with intial value of sum is 0): " << sum << endl;

//finding sum with initial value of sum is 100
sum = accumulate(v1.begin(), v1.end(), 100);
cout << "sum (with intial value of sum is 100): " << sum << endl;

return 0;
}
```

Output

```vector elements...
10 20 30 40 50
sum (with intial value of sum is 0): 150
sum (with intial value of sum is 100): 250
```

Top MCQs

Languages: » C » C++ » C++ STL » Java » Data Structure » C#.Net » Android » Kotlin » SQL
Web Technologies: » PHP » Python » JavaScript » CSS » Ajax » Node.js » Web programming/HTML
Solved programs: » C » C++ » DS » Java » C#
Aptitude que. & ans.: » C » C++ » Java » DBMS
Interview que. & ans.: » C » Embedded C » Java » SEO » HR
CS Subjects: » CS Basics » O.S. » Networks » DBMS » Embedded Systems » Cloud Computing
» Machine learning » CS Organizations » Linux » DOS
More: » Articles » Puzzles » News/Updates