请问下面这道JAVA题的代码是什么？

应该与OOP的概念有关，JAVA是老外教的，听不太懂。甚至都没什么基础哈哈

public class McmLength {
private int m;
private int cm;
private int hm;

public McmLength() {
}

public McmLength(int hm) {
    this.hm = hm;
}

public McmLength(double cm) {
    this.cm = (int) cm;
}

public McmLength(int m, int cm, int hm) {
    this.m = m;
    this.cm = cm;
    this.hm = hm;
}

public int add(int x, int y) {
    return x + y;
}

public int sub(int x, int y) {
    return x - y;
}

public double z(int x, int y) {
    return x / y;
}

public int s(int x, int y) {
    return x * y;
}

public int Max(int x, int y) {
    return Math.max(x, y);
}

public static void main(String[] args) {
    McmLength M1 = new McmLength();
    McmLength M2 = new McmLength(2);
    McmLength M3 = new McmLength(2.3);
    McmLength M4 = new McmLength(1, 2, 3);
    System.out.println(M1);
    System.out.println(M2);
    System.out.println(M3);
    System.out.println(M4.add(1, 2));
    System.out.println(M4.sub(3, 4));
    System.out.println(M4.z(5, 6));
    System.out.println(M4.s(7, 8));
    System.out.println(M4.Max(9, 0));
}

}
你这题目都是翻译过来的吧？

class McmLength{
    private int m;
    private int cm;
    private int mm;
    public McmLength(int mm){
        this.mm = mm;
    }
    public McmLength(double cm){
        this.cm = (int) cm;
    }
    public McmLength(int m, int cm, int mm){
        this.m = m;
        this.cm = cm;
        this.mm = mm;
    }
    public McmLength(){
        this.m = this.cm = this.mm = 0;
    }
    public McmLength add(McmLength a){
        int temp = m * 1000 + cm*10 + mm + a.m*1000 + a.cm*10 + a.mm;
        McmLength res = new McmLength();
        res.m = Math.floorDiv(temp, 1000);
        res.cm = Math.floorDiv(temp-res.m * 1000, 10);
        res.mm = temp - res.m*1000- res.cm*10;
        return res;
    }
}

写了个加法，剩下的可以自己练习的写下。
有帮助点个采纳吧