CPP

sum of elements in c++ stl

accumulate(a.begin(), a.end(), 0)

Array sum in c++ stl

// C++ program to demonstrate working of accumulate()
#include <iostream> 
#include <numeric>     
using namespace std;
   
// User defined function that returns sum of
// arr[] using accumulate() library function.
int arraySum(int a[], int n) 
{
    int initial_sum  = 0; 
    return accumulate(a, a+n, initial_sum);
}
   
int main() 
{
    int a[] = {5 , 10 , 15} ;
    int n = sizeof(a)/sizeof(a[0]);
    cout << arraySum(a, n);
    return 0;
}

sum array c++

//Syntax
accumulate(first, last, sum);
accumulate(first, last, sum, myfun); 

first, last : first and last elements of range 
              whose elements are to be added
sum :  initial value of the sum
myfun : a function for performing any 
        specific task. For example, we can
        find product of elements between
        first and last.
//Example
  int a[] = {5 , 10 , 15} ;
  int res = accumulate(a,a+3,0); // 30