how to do sum of array elements in c++ code example

Example: sum array c++

array<int,10> a{1,2,3,4,5,6,7,8,9};
  int sum = 0;
//Method 1:
  sum = accumulatea(a.begin(), a.end(), 0);
//Method 2: 
  for(auto& i : a) sum+=i;