JAVA实现有理数的运算+JAVA中的适配器模式

水深无声 2022-07-28 10:53 168阅读 0赞

题目要求：

设计一个抽象类，声明有关算术运算的方法，并创建四个（或者一个）子类继承该抽象的类，完成进行加、减、乘、除四则运算。

整个题目总共经过了三轮完善，第一发没有利用抽象类，只是简单的实现了基本操作；第二枚用了四个子类去继承这个原有的抽象类，其中就用到了可以骗人的适配器模式，没有实现方法的重写，而是用的方法的重载；第三弹则是用一个子类去继承该抽象类，并重写了其中的抽象方法完成了运算。建议大家直接看第三种！

JAVA中的适配器模式：在学习抽象类的继承和接口的实现时，我们总是要全部重写其中的抽象方法，能不能不这么烦呢，有一种适配器模式，可以巧妙的使用，来达到这个目的。

Aa.java
    package cn.nefu.edu.zhihu;
    
    public interface Aa {
    	void a();
    	void b();
    
    }
    Ab.java
    package cn.nefu.edu.zhihu;
    
    public class Ab implements Aa{
    
    	public void a() {
    		// TODO Auto-generated method stub
    		
    	}
    
    	public void b() {
    		// TODO Auto-generated method stub
    		
    	}
    
    }
    Ac.java
    package cn.nefu.edu.zhihu;
    
    public class Ac extends Ab{
    	
    
    }

方法一代码：

Youlishu.java
    package cn.nefu.edu.zhihu;
    
    public class Youlishu {
    	int fenzi,fenmu;
    	Youlishu(){
    		
    	}
    	Youlishu(int fenzi,int fenmu){
    		this.fenzi=fenzi;
    		this.fenmu=fenmu;
    	}
    	
    	int gcd(int x,int y){
    		if(y==0)
    			return x;
    		else
    			return gcd(y,x%y);
    	}
    	
    	int lcm(int x,int y){
    		return x*y/gcd(x,y);
    	}
    	
    	Youlishu add(Youlishu a,Youlishu b){
    		Youlishu c=new Youlishu(0,0);
    		int d1,d2;
    		int lcmm=lcm(a.fenmu,b.fenmu);
    		c.fenmu=lcmm;
    		d1=lcmm/a.fenmu;
    		d2=lcmm/b.fenmu;
    		c.fenzi=d1*a.fenzi+d2*b.fenzi;
    		int d=gcd(c.fenzi,c.fenmu);
    		c.fenzi=c.fenzi/d;
    		c.fenmu=c.fenmu/d;
    		return c;
    	}
    	
    	Youlishu sub(Youlishu a,Youlishu b){
    		Youlishu c=new Youlishu(0,0);
    		int d1,d2;
    		int lcmm=lcm(a.fenmu,b.fenmu);
    		c.fenmu=lcmm;
    		d1=lcmm/a.fenmu;
    		d2=lcmm/b.fenmu;
    		c.fenzi=d1*a.fenzi-d2*b.fenzi;
    		int d=gcd(c.fenzi,c.fenmu);
    		c.fenzi=c.fenzi/d;
    		c.fenmu=c.fenmu/d;
    		return c;
    	}
    	
    	Youlishu cheng(Youlishu a,Youlishu b){
    		Youlishu c=new Youlishu(0,0);
    		c.fenzi=a.fenzi*b.fenzi;
    		c.fenmu=a.fenmu*b.fenmu;
    		int d=gcd(c.fenzi,c.fenmu);
    		c.fenzi=c.fenzi/d;
    		c.fenmu=c.fenmu/d;
    		return c;
    	}
    	Youlishu chu(Youlishu a,Youlishu b){
    		Youlishu c=new Youlishu(0,0);
    		c.fenzi=a.fenzi*b.fenmu;
    		c.fenmu=a.fenmu*b.fenzi;
    		int d=gcd(c.fenzi,c.fenmu);
    		c.fenzi=c.fenzi/d;
    		c.fenmu=c.fenmu/d;
    		return c;
    	}
    	//getxiaoshu()
    	void show(){
    		System.out.println(fenzi+"/"+fenmu);
    	}
    
    }
    
    Test1.java
    package cn.nefu.edu.zhihu;
    
    import java.util.Scanner;
    
    public class test1 {
    
    	
    	public static void main(String[] args) {
    		Youlishu a=new Youlishu(2,3);
    		Youlishu b=new Youlishu(3,2);
    		Youlishu c=new Youlishu(0,0);
    		c=c.add(a,b);
    		c.show();
    		c=c.sub(a,b);
    		c.show();
    		c=c.cheng(a,b);
    		c.show();
    		c=c.chu(a,b);
    		c.show();
    		System.out.println("Please Input Youlishu a and b:");
    		Scanner reader=new Scanner(System.in);
    		a.fenzi=reader.nextInt();
    		a.fenmu=reader.nextInt();
    		b.fenzi=reader.nextInt();
    		b.fenmu=reader.nextInt();
    		c=c.add(a,b);
    		c.show();
    		c=c.sub(a,b);
    		c.show();
    		c=c.cheng(a,b);
    		c.show();
    		c=c.chu(a,b);
    		c.show();
    	}
    }

方法二代码：

Yunsuan.java
    package cn.edu.nefu.zhihu;
    
    public abstract class Yunsuan {
    	int gcd(int a,int b){
    		if(b==0)
    			return a;
    		else
    			return gcd(b,a%b);
    	}
    	int lcm(int a,int b){
    		return a*b/gcd(a,b);
    	}
    	abstract Object add(Object a,Object b);
    	abstract Object sub(Object a,Object b);
    	abstract Object multi(Object a,Object b);
    	abstract Object divid(Object a,Object b);
    }
    Yunsuanzi.java
    package cn.edu.nefu.zhihu; //适配器模式
    
    public class Yunsuanzi extends Yunsuan{
    
    	@Override
    	Object add(Object a, Object b) {
    		// TODO Auto-generated method stub
    		return null;
    	}
    
    	@Override
    	Object divid(Object a, Object b) {
    		// TODO Auto-generated method stub
    		return null;
    	}
    
    	@Override
    	Object multi(Object a, Object b) {
    		// TODO Auto-generated method stub
    		return null;
    	}
    
    	@Override
    	Object sub(Object a, Object b) {
    		// TODO Auto-generated method stub
    		return null;
    	}
    }
    Add.java
    package cn.edu.nefu.zhihu;
    
    public class Add extends Yunsuanzi {
    		Object add(Youlishu a,Youlishu b){
    			Youlishu c = new Youlishu(0,0);
    			int d1,d2;
    			int lcmm=lcm(a.fenmu,b.fenmu);
    			c.fenmu=lcmm;
    			d1=lcmm/a.fenmu;
    			d2=lcmm/b.fenmu;
    			c.fenzi=d1*a.fenzi+d2*b.fenzi;
    			int d=gcd(c.fenzi,c.fenmu);
    			c.fenzi=c.fenzi/d;
    			c.fenmu=c.fenmu/d;
    			return c;
    		}
    }
    Sub.java
    package cn.edu.nefu.zhihu;
    
    public class Sub extends Yunsuanzi{
    	Object sub(Youlishu a,Youlishu b){  //注意：方法的重载，不是重写
    		Youlishu c=new Youlishu(0,0);
    		int d1,d2;
    		int lcmm=lcm(a.fenmu,b.fenmu);
    		c.fenmu=lcmm;
    		d1=lcmm/a.fenmu;
    		d2=lcmm/b.fenmu;
    		c.fenzi=d1*a.fenzi-d2*b.fenzi;
    		int d=gcd(c.fenzi,c.fenmu);
    		c.fenzi=c.fenzi/d;
    		c.fenmu=c.fenmu/d;
    		return c;
    	}
    }
    Multi.java
    package cn.edu.nefu.zhihu;
    
    public class Multi extends Yunsuanzi {
    	Object multi(Youlishu a,Youlishu b){
    		Youlishu c=new Youlishu(0,0);
    		c.fenzi=a.fenzi*b.fenzi;
    		c.fenmu=a.fenmu*b.fenmu;
    		int d=gcd(c.fenzi,c.fenmu);
    		c.fenzi=c.fenzi/d;
    		c.fenmu=c.fenmu/d;
    		return c;
    	}
    }
    Divid.java
    package cn.edu.nefu.zhihu;
    
    public class Divid extends Yunsuanzi{
    	 Object divid(Youlishu a,Youlishu b){
    		Youlishu c=new Youlishu(0,0);
    		c.fenzi=a.fenzi*b.fenmu;
    		c.fenmu=a.fenmu*b.fenzi;
    		int d=gcd(c.fenzi,c.fenmu);
    		c.fenzi=c.fenzi/d;
    		c.fenmu=c.fenmu/d;
    		return c;
    	}
    }
    Youlishu.java
    package cn.edu.nefu.zhihu;
    
    public class Youlishu extends Object{
    	int fenzi,fenmu;
    	Youlishu(){
    		
    	}
    	Youlishu(int fenzi,int fenmu){
    		this.fenzi=fenzi;
    		this.fenmu=fenmu;
    	}
    	void show(){
    		System.out.println(fenzi+"/"+fenmu);
    	}
    }
    Test.java
    package cn.edu.nefu.zhihu;
    import java.util.Scanner;
    public class test {
    
    	public static void main(String[] args){
    		Scanner reader=new Scanner(System.in);
    		int x1,y1,x2,y2;
    		x1=reader.nextInt();
    		y1=reader.nextInt();
    		x2=reader.nextInt();
    		y2=reader.nextInt();
    		Youlishu ylsa=new Youlishu(x1,y1);
    		Youlishu ylsb=new Youlishu(x2,y2);
    		Youlishu ylsc=new Youlishu(0,0);
    		Add jia=new Add();
    		ylsc=(Youlishu) jia.add(ylsa, ylsb);
    		ylsc.show();
    		
    		Sub jian=new Sub();
    		ylsc=(Youlishu) jian.sub(ylsa, ylsb);
    		ylsc.show();
    		
    		Multi cheng=new Multi();
    		ylsc=(Youlishu) cheng.multi(ylsa, ylsb);
    		ylsc.show();
    		
    		Divid chu=new Divid();
    		ylsc=(Youlishu) chu.divid(ylsa, ylsb);
    		ylsc.show();
    	}
    }

方法三代码实现：

Yunsuan.java
    package cn.edu.nefu.zhihu;
    public abstract class Yunsuan {
    	public abstract Object add(Object a);
    	public abstract Object sub(Object a);
    	public abstract Object multi(Object a);
    	public abstract Object divid(Object a);
    	public int gcd(int a,int b){
    		if(b==0)
    			return a;
    		else
    			return gcd(b,a%b);
    	}
    	public int lcm(int a,int b){
    		return a*b/gcd(a,b);
    	}
    }
    
    YouLiShu.java
    package cn.edu.nefu.zhihu;
    
    public class YouLiShu extends Yunsuan{
    	int fenzi,fenmu;
    	public YouLiShu(){}
    	public YouLiShu(int fenzi ,int fenmu){
    		this.fenzi=fenzi;
    		this.fenmu=fenmu;
    	}
    	@Override
    	public YouLiShu add(Object a) {
    		YouLiShu y=(YouLiShu)a;
    		YouLiShu z=new YouLiShu();
    		int lcmm=lcm(fenmu,y.fenmu);
    		z.fenmu=lcmm;
    		int d1,d2;
    		d1=lcmm/fenmu;
    		d2=lcmm/y.fenmu;
    		z.fenzi=d1*fenzi+d2*y.fenzi;
    		int gcdd2=gcd(z.fenmu,z.fenzi);
    		z.fenmu=z.fenmu/gcdd2;
    		z.fenzi=z.fenzi/gcdd2;
    		return z;
    	}
    	@Override
    	public YouLiShu divid(Object a) {
    		YouLiShu y=(YouLiShu)a;
    		YouLiShu z=new YouLiShu();
    		z.fenmu=fenmu*y.fenzi;
    		z.fenzi=fenzi*y.fenmu;
    		int gcdd2=gcd(z.fenmu,z.fenzi);
    		z.fenmu=z.fenmu/gcdd2;
    		z.fenzi=z.fenzi/gcdd2;
    		return z;
    	}
    	@Override
    	public YouLiShu multi(Object a) {
    		YouLiShu y=(YouLiShu)a;
    		YouLiShu z=new YouLiShu();
    		z.fenmu=fenmu*y.fenmu;
    		z.fenzi=fenzi*y.fenzi;
    		int gcdd2=gcd(z.fenmu,z.fenzi);
    		z.fenmu=z.fenmu/gcdd2;
    		z.fenzi=z.fenzi/gcdd2;
    		return z;
    	}
    	@Override
    	public YouLiShu sub(Object a) {
    		YouLiShu y=(YouLiShu)a;
    		YouLiShu z=new YouLiShu();
    		z.fenmu=fenmu*y.fenmu;
    		z.fenzi=fenzi*y.fenmu-fenmu*y.fenzi;
    		int gcdd2=gcd(z.fenmu,z.fenzi);
    		z.fenmu=z.fenmu/gcdd2;
    		z.fenzi=z.fenzi/gcdd2;
    		return z;
    	}
    	public String toString(){
    		return (fenzi+"/"+fenmu);
    	}
    	public double toXiaoShu(){
    		return fenzi*1.0/fenmu;
    	}
    }
    Test.java
    package cn.edu.nefu.zhihu;
    public class Test {
    
    	public static void main(String[] args) {
    		YouLiShu x=new YouLiShu(2,3);//匿名对象
    		YouLiShu y=new YouLiShu();
    		y=x.add(new YouLiShu(3,2));
    		System.out.println(y.toString());
    		System.out.println(y.toXiaoShu());
    		y=x.sub(new YouLiShu(1,3));
    		System.out.println(y.toString());
    		System.out.println(y.toXiaoShu());
    		y=x.multi(new YouLiShu(1,4));
    		System.out.println(y.toString());
    		System.out.println(y.toXiaoShu());
    		y=x.divid(new YouLiShu(3,2));
    		System.out.println(y.toString());
    		System.out.println(y.toXiaoShu());
    	}
    }