JAvaでのSet,Map,Stackの簡単な使い方

 1 import java.util.Iterator;
 2 import java.util.Stack;
 3 import java.io.*;
 4 import java.util.Set;
 5 import java.util.Map;
 6 import java.util.HashMap;
 7 import java.util.TreeSet;
 8 public class StackUsing{
 9    public static void main(String args[]) throws IOException{
10       Stack<Integer> s = new Stack<Integer>();
11       int i;
12       for(i=0; i<10; ++i)
13          s.push(i); 
14    
15       //it.hasNext()              ，  true！ it.next()             ，           
16       for(Iterator<Integer>it = s.iterator(); it.hasNext(); ){//       
17          System.out.println(it.next());
18       }
19    
20       for(Integer k:s){
21            System.out.println(k);
22       }
23     
24       while(!s.empty()){//       
25          System.out.println(s.pop());
26       }
27 
28      Set<Integer> st = new TreeSet<Integer>();
29      for(i=0; i<10; ++i)
30         st.add(i);
31      for(Integer k: st){//            
32         System.out.println(k);
33      }
34      
35      for(Iterator<Integer>it = st.iterator(); it.hasNext(); ){//             
36          System.out.println(it.next());
37      }
38 
39      Set<myInteger> stp = new TreeSet<myInteger>();//             
40      for(i=0; i<10; ++i)
41        stp.add(new myInteger(i, i*2)); 
42     
43      for(myInteger x:stp){
44         System.out.println(x.first + " " + x.second);
45      }
46 
47      Map<String, Integer>mp = new HashMap<String, Integer>();
48      String str;
49      BufferedReader myInput = new BufferedReader(new InputStreamReader(System.in));
50 
51      str=myInput.readLine();
52      while(str.compareTo("#")!=0){
53          Integer cnt=mp.get(str);
54          if(cnt==null)
55             cnt=new Integer(0);
56          ++cnt;
57          mp.put(str, cnt);
58          str=myInput.readLine();
59      }
60      
61      ///3   Map   
62      for(String ss : mp.keySet()){
63         System.out.println(ss + " " + mp.get(ss));
64      }
65      System.out.println("**********************");
66      
67      //          ，          ；             ，                 
68      for(Map.Entry<String, Integer>entry : mp.entrySet()){//               set   。    set            Map.Entry
69         System.out.println(entry.getKey() + " " + entry.getValue());
70      }
71      System.out.println("**********************");
72 
73      for(Iterator<Map.Entry<String, Integer> > it = mp.entrySet().iterator(); it.hasNext(); ){
74          Map.Entry<String, Integer>entry=it.next();
75          System.out.println(entry.getKey() + " " + entry.getValue());
76      }
77    }
78 }
79 
80 class myInteger implements Comparable{
81     int first;
82     int second;
83     public myInteger(int a, int b){
84          first=a;
85          second=b;
86     }
87     public myInteger(){
88         first=0;
89         second=0;
90     }
91     public int compareTo(Object x){
92         if(first>((myInteger)x).first) return -1;//             
93         else if(first==((myInteger)x).first) return 0;
94         else return 1;
95     }
96 }