第一次作业

package com.test;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Scanner;

public class demo {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("请输入字符串：");
        String  s= sc.nextLine();

        
        //String s = "Hello World My First Unit Test";
        String[] str =s.split(" ");
        Map map = new HashMap<String, String>();
        
        for (int i = 0; i < str.length; i++) {
            //System.out.println(str[i]);
            if(map.containsKey(str[i])){
                String value = (String) map.get(str[i]);
                int a = Integer.parseInt(value) + 1;
                String value1 = String.valueOf(a);
                map.remove(str[i]);
                map.put(str[i], value1);
            }
            else{
                map.put(str[i], "1");
                
            }
        }
        
        Iterator<Map.Entry<String, String>> it = map.entrySet().iterator();
          while (it.hasNext()) {
           Map.Entry<String, String> entry = it.next();
           System.out.println(entry.getKey()+ "  " + entry.getValue());
          }
    }

}

package com.test;

import java.util.Scanner;

public class demo2 {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("请输入字符串：");
        String  s= sc.nextLine();
        
        //String s = "how are you";
        String[] str = s.split(" ");
        StringBuffer ss = new StringBuffer();
        for (int i = str.length-1; i >=0; i--) {
            //System.out.println(str[i]);
            ss.append(str[i] + " ");
        }
        
        System.out.println("new: "+ss);
    }

}