C#---并行化Parallel

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

namespace parallel
{
class ParallelDemon
{
public int[] arr = new int[20];
public void init()
{
for (int i = 0; i < 20; i++)
arr[i] = i;
}
public void thread1()
{
Parallel.For(0, 5, i =>
{
Console.Write(i + " ");
});
Console.WriteLine();
}
public void thread2()
{
Parallel.For(5, 10, i =>
{
Console.Write(i + " ");
});
Console.WriteLine();
}
public void thread3()
{
Parallel.For(10, 15, i =>
{
Console.Write(i + " ");
});
Console.WriteLine();
}
}
class Program
{
static void Main(string[] args)
{
ParallelDemon t = new ParallelDemon();
lock(t.arr)
{
t.thread1();
t.thread2();
t.thread3();
}
Console.ReadLine();
}
}
}