どうして、この出力になるのか教えてください。

package chapter04;

public class IncDec {

    public static void main(String[] args) {
        int a = 10, b = 10, c = 0, d = 0;

        System.out.println("a:" + a + " b:" + b + " c:" + c + " d:" + d);

        c = a--;
        d = ++b;
        System.out.println("\nc = a--; d = ++b;");
        System.out.println("a:" + a + " b:" + b + " c:" + c + " d:" + d);

        c = --a;
        d = b++;
        System.out.println("\nc = --a; d = b++;");
        System.out.println("a:" + a + " b:" + b + " c:" + c + " d:" + d);

        d = ++a - b--;
        System.out.println("\nd = ++a - b--;");
        System.out.println("a:" + a + " b:" + b + " c:" + c + " d:" + d);

        a--;
        ++b;
        System.out.println("\na--; ++b;");
        System.out.println("a:" + a + " b:" + b + " c:" + c + " d:" + d);
    }

}

＜出力＞

a:10 b:10 c:0 d:0

c = a--; d = ++b;
a:9 b:11 c:10 d:11

c = --a; d = b++;
a:8 b:12 c:8 d:11

d = ++a - b--;
a:9 b:11 c:8 d:-3

a--; ++b;
a:8 b:12 c:8 d:-3