This is very elementary -- but kindly explain -- can someone please explain why the output of the code below is this:

OUTPUT:
a = 2
b = 3
c = 4
d = 1

How did a = 2 as above? Thanks.

Code:
public class MainClass {
   public static void main(String args[]) {
    int a = 1;
    int b = 2;
    int c;
    int d;
    c = ++b;
    d = a++;
    c++;
    System.out.println("a = " + a);
    System.out.println("b = " + b);
    System.out.println("c = " + c);
    System.out.println("d = " + d);
  }
}