Hashmap实现来计算每个字符的出现次数 [英] Hashmap implementation to count the occurences of each character

问题描述

下面的代码是计算每个字符的出现次数，它应该打印计数。
但是用代码我试过我只得到一个1我不知道我应该做的更改。请帮助我。

The below code is to count the occurence of each character and it should print the count. But with the code i have tried i get only a 1 I don't know the changes i should make. Please help me.

import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Map;

class Count_CharMap {
public static void main(String[] args) {
    try
    {
        FileInputStream file = new FileInputStream("D:\\trial.txt");
        DataInputStream dis = new DataInputStream(file);
        BufferedReader br = new BufferedReader(new InputStreamReader(dis));
        String Contents="";
        String str="";

        while ((Contents = br.readLine()) != null) {
            str+=Contents;
        }

        char[]char_array =str.toCharArray();
        int count = 0;
        char ch = char_array[count];
        Map<Character,Integer> charCounter=new HashMap<Character,Integer>();
        for(int i=0;i<str.length();i++)
        {
            if(charCounter.containsKey(char_array[i]))
            {
                charCounter.put(ch, charCounter.get(ch)+1);
            } 
            else
            {
                charCounter.put(ch, 1);
            }
       }

       for(Character key:charCounter.keySet())
       {
           System.out.println(key+""+charCounter.get(key));
       }
    } 
    catch(IOException e1){
        System.out.println(e1);
    }
    }
}

实际输出应该像
如果我在我的trial.txt中有abcdabc，它应该打印一个2 b 2c 2 d 1。

Actual output should be like If i have abcdabc in my trial.txt it should print a 2 b 2c 2 d 1.

推荐答案

通过每次执行循环将字符集设置为相同的字符。

You're leaving char ch set as the same character through each execution of the loop.

它应该是：

ch = char_array[i]; 
if(charCounter.containsKey(ch)){
     charCounter.put(ch, charCounter.get(ch)+1);
}
else
{
    charCounter.put(ch, 1);
}

这篇关于Hashmap实现来计算每个字符的出现次数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！