How to sum up an array of integers in C#

Question

Is there a better shorter way than iterating over the array?

int[] arr = new int[] { 1, 2, 3 };
int sum = 0;
for (int i = 0; i < arr.Length; i++)
{
    sum += arr[i];
}

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clarification:

Better primary means cleaner code but hints on performance improvement are also welcome. (Like already mentioned: splitting large arrays).

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It's not like I was looking for killer performance improvement - I just wondered if this very kind of syntactic sugar wasn't already available: "There's String.Join - what the heck about int[]?".

Answer 1

Provided that you can use C# 3.5 and LINQ, try

int sum = arr.Sum(i => i);

Answer 2

Yes there is. With .NET 3.5:

int sum = arr.Sum();
Console.WriteLine(sum);

If you're not using .NET 3.5 you could do this:

int sum = 0;
Array.ForEach(arr, delegate(int i) { sum += i; });
Console.WriteLine(sum);

Answer 3

With LINQ:

arr.Sum()

Answer 4

It depends on how you define better. If you want the code to look cleaner, you can use .Sum() as mentioned in other answers. If you want the operation to run quickly and you have a large array, you can make it parallel by breaking it into sub sums and then sum the results.

Answer 5

Using foreach would be shorter code, but probably do exactly the same steps at runtime after JIT optimization recognizes the comparison to Length in the for-loop controlling expression.