SumOfEvens, C# - rextester

SumOfEvens

//Rextester.Program.Main is the entry point for your code. Don't change it.
//Compiler version 4.0.30319.17929 for Microsoft (R) .NET Framework 4.5

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;
using System.Threading.Tasks;

namespace Rextester
{
    public class Program
    {
        public static void Main(string[] args)
        {
            Random r = new Random (1001);
            int n = r.Next(1000);
            
            int[] lotsOfInts = new int[n];
            for (int i=0;i<n;i++) lotsOfInts[i] = r.Next(1000);
            
            int s1 = SumOfEvensLinq (lotsOfInts), 
                s2 = SumOfEvensIteration (lotsOfInts),
                s3 = SumOfEvensPFor (lotsOfInts),
                s4 = SumOfEvensPLinq (lotsOfInts);
            
            Console.WriteLine(s1 == s2);
            Console.WriteLine(s2 == s3);
            Console.WriteLine(s3 == s4);
        }
        
        
        // this does filtering first, probably worst
        static int SumOfEvensLinq(int[] lotsOfInts)
        {
            // return the sum of all of the even numbers in lotsOfInts
            // don’t worry about the possibility of the sum 
            // overflowing an int
            return lotsOfInts.Where(i => i%2==0).Sum();        
        }
        
        static int SumOfEvensPLinq(int[] lotsOfInts)
        {
            int sum = 0;
            Parallel.ForEach(lotsOfInts, x=> { if (x % 2 == 0) sum += x; });
            return sum;
        }
        
        static int SumOfEvensIteration(int[] lotsOfInts)
        {
            int sum=0;        
            for (int i=0; i<lotsOfInts.Length; i++)
                if (lotsOfInts[i] % 2 == 0)
                  sum += lotsOfInts[i];            
            return sum;
        }
        
        static int SumOfEvensPFor(int[] lotsOfInts)
        {
            int sum=0;        
            Parallel.For (0,lotsOfInts.Length, i=> { if (lotsOfInts[i] % 2 == 0) sum += lotsOfInts[i]; });
            return sum;
        }
        
    }

}


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