58. 인터페이스 배열로 규칙 차례로 적용하기

1interface Rule {
2    int apply(int x);
3 
4    default String name() {
5        return "R";
6    }
7}
8 
9class Twice implements Rule {
10    public int apply(int x) {
11        return x * 2;
12    }
13}
14 
15class Minus implements Rule {
16    int d;
17 
18    Minus(int d) {
19        this.d = d;
20    }
21 
22    public int apply(int x) {
23        return x - d;
24    }
25 
26    public String name() {
27        return "M" + d;
28    }
29}
30 
31class Square implements Rule {
32    public int apply(int x) {
33        return x * x;
34    }
35 
36    public String name() {
37        return "S";
38    }
39}
40 
41public class Main {
42    public static void main(String[] args) {
43        Rule[] rules = {new Minus(3), new Twice(), new Square(), new Minus(10)};
44        int v = 5;
45        for (Rule r : rules) {
46            v = r.apply(v);
47            System.out.println(r.name() + ":" + v);
48        }
49        System.out.println("최종=" + v);
50    }
51}