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

namespace test {

    class Program {

        static IEnumerable<int>nums(int count){
            for (var i = 0; i < count; i++) yield return i;
        }
        static int[] numsarr = nums(10000000).ToArray();

        static int test1() {
            var sum = 0;
            foreach (var x in nums(10000000)) sum += x;
            return sum;
        }
        static int test2() {
            var sum = 0;
            for (int i = 0; i < numsarr.Length; i++) sum += numsarr[i];
            return sum;
        }

        static void Main(string[] args) {
            Console.WriteLine(test1());
            Console.WriteLine(test2());
            GC.Collect(2, GCCollectionMode.Forced);
            GC.Collect(2, GCCollectionMode.Forced);
            var sw = System.Diagnostics.Stopwatch.StartNew();
            test1();
            Console.WriteLine(sw.Elapsed);
            GC.Collect(2, GCCollectionMode.Forced);
            GC.Collect(2, GCCollectionMode.Forced);
            sw = System.Diagnostics.Stopwatch.StartNew();
            test2();
            Console.WriteLine(sw.Elapsed);
        }
    }
}