04/07 学习记录1

学习了HashMap的基本用法。

做了道题练习一下，随机产生50个10到50的数字，统计每个数字出现次数。按照数字的升序打印

package map;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Random;
import java.util.TreeSet;

public class HomeWork {
    public static void main(String[] args) {

        Random generator = new Random();
        int i = 0;
        TreeSet<Integer> ts = new TreeSet<Integer>();
        HashMap<Integer, Integer> hm = new HashMap<Integer, Integer>();

        while (i < 50) {
            Integer key = new Integer(generator.nextInt(41) + 10);
            ts.add(key);

            if (hm.containsKey(key)) {
                Integer tmp = hm.get(key);
                hm.put(key, new Integer(tmp.intValue() + 1));
            } else {
                hm.put(key, new Integer(1));
            }

            i++;
        }

        // display

        int max_value = 0;
        Integer max_key = null;
        for (Iterator<Integer> iter = ts.iterator(); iter.hasNext();) {
            Integer tmp = iter.next();
            Integer value = hm.get(tmp);
            if (value.intValue() > max_value) {
                max_value = value.intValue();
                max_key = tmp;
            }
            System.out.println(tmp + " : " + value);
        }

        System.out.println("Max key is " + max_key + " max value associed is "
                + max_value);

    }
}