code snippet ? functionality ??

Question

Hii

static void Main()

        {

            int i, j = 1, k;

            for (i = 0; i < 5; i++)

            {

                k =j++ + ++j;

                Console.WriteLine(k+"  ");

            }

            Console.ReadKey();

        }

In he above code .. i am getting out put as 4 8 12 16 20 ... well its compiler generated output it cant be wrong but the thing is i am confused .. with the block of code 
             K= j++ + ++J ;
Here acc to pre & post increment operation mechanism say initially j=1 next step j++ it remains 1 only after that ++j it gets 2 so 1+2 should be 3 but y am i getting 4 ..

Hope u got my point TY