疯狂java讲义习题7.3

题目描述：
给定["a","b","a","b","c","a","b","c","b"]字符串数组，然后使用Map的Key来保存数组中字符串元素，value保存该字符串出现的次数，最后统计出各字符串元素的出现次数
代码如下：

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1. import java.io.*;
   
2. import java.util.*;
   
3. public class cmd {
   
4.     public static void main(String args[])
   
5.     {
   
6.         String str[] = {"a","b","a","b","c","a","b","c","b"};
   
7.         HashMap hm = new HashMap();
   
8.         int count1 = 0,count2 = 0,count3 = 0;
   
9.         for (int i = 0;i < str.length;i++)
   
10.         {
    
11.             
    
12.             if (str[i].equals("a"))
    
13.             {
    
14.                 
    
15.                 count1++;
    
16.             }
    
17.             else if (str[i].equals("b"))
    
18.             {
    
19.                 count2++;
    
20.             }
    
21.             else if (str[i].equals("c"))
    
22.             {
    
23.                 count3++;
    
24.             }
    
25.             else{}
    
26.         }
    
27.         
    
28.         hm.put("a",count1);
    
29.         hm.put("b",count2);
    
30.         hm.put("c",count3);
    
31.         System.out.println(hm);
    
32.         
    
33.         
    
34.     }
    
35.     
    
36. }

运行结果如下：
{b=4, c=2, a=3}