Java常见容器练习-----（散列表Hash）

  代码：

package HashMap;import java.util.HashMap;import java.util.Scanner;public class Coin {    	PRivate HashMap<Integer, String> coinnames =new HashMap<Integer,String>();    	public Coin(){		coinnames.put(1,"penny");		coinnames.put(10,"dime");		coinnames.put(25,"quarter");		coinnames.put(50,"half-dolar");		coinnames.put(50,"五毛");		System.out.println(coinnames.keySet().size());//键的个数		System.out.println(coinnames);//输出HashMap中所有键-值组成的表		for(Integer k:coinnames.keySet())//得到每一个Key		{			String s=coinnames.get(k);//得到每一个值			System.out.print(s+" ");		}		System.out.println();			}		public String getName(int amount){		if(coinnames.containsKey(amount)){			return coinnames.get(amount);		}		else{			return "NOT FOUND!";		}	}	public static void main(String[] args) {		// TODO Auto-generated method stub       Scanner in=new Scanner(System.in);       int amount=in.nextInt();       Coin coin=new Coin();       String name=coin.getName(amount);// 根据钱数得出钱名       System.out.println("----------------------");       System.out.println(name);	}}运行结果：
504{1=penny, 50=五毛, 25=quarter, 10=dime}penny 五毛 quarter dime ----------------------五毛