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

• Difficulty Level : Basic
• Last Updated : 19 May, 2022

Given a vector, find the sum of the elements of this vector using STL in C++.
Example:

```Input: vec = {1, 45, 54, 71, 76, 12}
Output: 259

Input: vec = {1, 7, 5, 4, 6, 12}
Output: 35```

Approach: Sum can be found with the help of accumulate() function provided in STL.
Syntax:

`accumulate(first_index, last_index, initial value of sum);`

Time Complexity: It is linear in the distance between first_index and last_index i.e if your  vector contains n number of elements between two given indices , the time complexity will be O(n).

## CPP

 `// C++ program to find the sum``// of Array using accumulate() in STL` `#include ``using` `namespace` `std;` `int` `main()``{``    ``// Get the vector``    ``vector<``int``> a = { 1, 45, 54, 71, 76, 12 };` `    ``// Print the vector``    ``cout << ``"Vector: "``;``    ``for` `(``int` `i = 0; i < a.size(); i++)``        ``cout << a[i] << ``" "``;``    ``cout << endl;` `    ``// Find the sum of the vector``    ``cout << ``"\nSum = "``         ``<< accumulate(a.begin(), a.end(), 0);``    ``return` `0;``}`
Output:
```Vector: 1 45 54 71 76 12

Sum = 259```

My Personal Notes arrow_drop_up