Sample code to add the elements of an integer List using a 'foreach' loop

listadd.cs

/*
Copyright 2017 Intel Corporation. 

The source code, information and material ("Material") contained herein 
is owned by Intel Corporation or its suppliers or licensors, and title 
to such Material remains with Intel Corporation or its suppliers or 
licensors. The Material contains proprietary information of Intel or its 
suppliers and licensors. The Material is protected by worldwide 
copyright laws and treaty provisions. No part of the Material may be 
used, copied, reproduced, modified, published, uploaded, posted, 
transmitted, distributed or disclosed in any way without Intel's prior 
express written permission. No license under any patent, copyright or 
other intellectual property rights in the Material is granted to or 
conferred upon you, either expressly, by implication, inducement, 
estoppel or otherwise. Any license under such intellectual property 
rights must be express and approved by Intel in writing. 

Unless otherwise agreed by Intel in writing, you may not remove or alter 
this notice or any other notice embedded in Materials by Intel or 
Intel's suppliers or licensors in any way. 
*/

using System;
using System.Linq;
using System.Collections.Generic;

namespace ListSample
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Starting calculation...");            
            List<int> numbers = Enumerable.Range(1,10000).ToList();
            var total = 0;
            for (var i = 0; i < 100000; i++)
            {
                total = ListAdd(numbers);
            }
            
            Console.WriteLine("Calculation complete");
            Console.WriteLine("Sum of list elements is " + total);
        }

        static int ListAdd(List<int> candidateList)
        {
            var result = 0;
            foreach (var item in candidateList)
            {
                result += item;
            }
            
            return result;
        }        
    }
}