深入理解算术运算符自加1与自减1

/*
      深入理解算术运算符"++"与"--"  
*/
public class Homework01{
    public static void main(String[] args) {
        int x = 10;
        int a = x + x++;    //因为++在变量后，所以是先赋值后自加1；该行代码执行结束：a=20；x=11
        System.out.println("a =" + a);  //a =20
        System.out.println("x =" + x);  //x =11
        int b = x + ++x;    //因为++在变量前，所以是先自加1再赋值；该行代码运行结束：b=23；x=12
        System.out.println("b =" + b);  //b =23
        System.out.println("x =" + x);  //x =12
        int c = x + x--;    //因为--在变量后，所以是先赋值后自减1；该行代码运行结束：c=24；x=11
        System.out.println("c =" + c);  //c =24
        System.out.println("x =" + x);  //x =11
        int d = x + --x;    //因为--在变量前，所以是先自减1后赋值；该行代码运行结束：d=21；x=10
        System.out.println("d =" + d);  //d =21
        System.out.println("x =" + x);  //x =10
    }
}