集合类

水深无声 2022-08-21 11:42 124阅读 0赞

1.有集合A=\{1,2,3,4\}和B=\{1,3,7,9,11\},编写一个应用程序输出A和B的交集、并集和差集。

具体运用HashSet来实现即可。

代码实现：

package cn.edu.nefu.zhihu;
    
    import java.util.HashSet;
    import java.util.Iterator;
    
    public class Fanxing {
    
    	public static void main(String[] args) {
    		Integer one=new Integer(1);
    		Integer two=new Integer(2);
    		Integer three=new Integer(3);
    		Integer four=new Integer(4);
    		Integer seven=new Integer(7);
    		Integer nine=new Integer(9);
    		Integer eleven=new Integer(11);
    		HashSet<Integer> A=new HashSet<Integer>();
    		HashSet<Integer> B=new HashSet<Integer>();
    		HashSet<Integer> tempSetA1=new HashSet<Integer>();
    		HashSet<Integer> tempSetA2=new HashSet<Integer>();
    		HashSet<Integer> tempSetA3=new HashSet<Integer>();
    		A.add(one);
    		A.add(two);
    		A.add(three);
    		A.add(four);
    
    		B.add(one);
    		B.add(three);
    		B.add(seven);
    		B.add(nine);
    		B.add(eleven);
    		
    		tempSetA1=(HashSet<Integer>)A.clone();
    		tempSetA2=(HashSet<Integer>)A.clone();
    		tempSetA3=(HashSet<Integer>)A.clone();
    		
    		tempSetA1.retainAll(B);
    		Iterator<Integer> it1=tempSetA1.iterator();
    		int num1=tempSetA1.size();
    		System.out.println("集合A和集合B的交集元素个数为："+num1);
    		System.out.println("集合A和集合B的交集为：");
    		while(it1.hasNext()){
    			Integer ite1=it1.next();
    			System.out.print(ite1.intValue()+" ");
    		}System.out.println();
    		
    		tempSetA2.addAll(B);
    		Iterator<Integer> it2=tempSetA2.iterator();
    		int num2=tempSetA2.size();
    		System.out.println("集合A和集合B的并集元素个数为："+num2);
    		System.out.println("集合A和集合B的并集为：");
    		while(it2.hasNext()){
    			Integer ite2=it2.next();
    			System.out.print(ite2.intValue()+" ");
    		}System.out.println();
    		
    		tempSetA3.removeAll(B);
    		Iterator<Integer> it3=tempSetA3.iterator();
    		int num3=tempSetA3.size();
    		System.out.println("集合A和集合B的差集元素个数为："+num3);
    		System.out.println("集合A和集合B的差集为：");
    		while(it3.hasNext()){
    			Integer ite3=it3.next();
    			System.out.print(ite3.intValue()+" ");
    		}System.out.println();
    	}
    }

2.有十个硬盘，有两个重要的属性：价格和容量。编写一个应用程序，使用TreeMap<K,V>类，分别按照价格和容量排序输出十个硬盘的详细信息。

代码实现：

package cn.edu.nefu.zhihu;
    
    import java.util.Collection;
    import java.util.Iterator;
    import java.util.TreeMap;
    
    public class Test {
    
    	public static void main(String[] args) {
    		YingPan yp1=new YingPan("周白菜",1,10);
    		YingPan yp2=new YingPan("桃花彤",2,9);
    		YingPan yp3=new YingPan("香橙武",3,8);
    		YingPan yp4=new YingPan("苹果杰",4,7);
    		YingPan yp5=new YingPan("梨子壕",5,6);
    		YingPan yp6=new YingPan("香蕉睿",6,5);
    		YingPan yp7=new YingPan("葡萄天",7,4);
    		YingPan yp8=new YingPan("腊鸡毅",8,3);
    		YingPan yp9=new YingPan("芒果军",9,2);
    		YingPan yp10=new YingPan("柠檬兽",10,1);
    		TreeMap<MyKey,YingPan> treemap=new TreeMap<MyKey,YingPan>();
    		
    		treemap.put(new MyKey(yp1.price),yp1);
    		treemap.put(new MyKey(yp2.price),yp2);
    		treemap.put(new MyKey(yp3.price),yp3);
    		treemap.put(new MyKey(yp4.price),yp4);
    		treemap.put(new MyKey(yp5.price),yp5);
    		treemap.put(new MyKey(yp6.price),yp6);
    		treemap.put(new MyKey(yp7.price),yp7);
    		treemap.put(new MyKey(yp8.price),yp8);
    		treemap.put(new MyKey(yp9.price),yp9);
    		treemap.put(new MyKey(yp10.price),yp10);
    		
    		int num=treemap.size();
    		System.out.println("树映射中有"+num+"个对象:");
    		Collection<YingPan> collection=treemap.values();
    		Iterator<YingPan> it=collection.iterator();
    		while(it.hasNext()){
    			YingPan ite=it.next();
    			System.out.println("硬盘名:"+ite.name+" 硬盘价格:"+ite.price+"  硬盘容量："+ite.rong);
    		}
    		treemap.clear();
    		
    		treemap.put(new MyKey(yp1.rong),yp1);
    		treemap.put(new MyKey(yp2.rong),yp2);
    		treemap.put(new MyKey(yp3.rong),yp3);
    		treemap.put(new MyKey(yp4.rong),yp4);
    		treemap.put(new MyKey(yp5.rong),yp5);
    		treemap.put(new MyKey(yp6.rong),yp6);
    		treemap.put(new MyKey(yp7.rong),yp7);
    		treemap.put(new MyKey(yp8.rong),yp8);
    		treemap.put(new MyKey(yp9.rong),yp9);
    		treemap.put(new MyKey(yp10.rong),yp10);
    		int num1=treemap.size();
    		System.out.println("树映射中有"+num1+"个对象:");
    		Collection<YingPan> collection1=treemap.values();
    		Iterator<YingPan> it1=collection.iterator();
    		while(it1.hasNext()){
    			YingPan ite=it1.next();
    			System.out.println("硬盘名:"+ite.name+" 硬盘价格:"+ite.price+"  硬盘容量："+ite.rong);
    		}
    		treemap.clear();
    	}
    }