How to resolve this task?

Question about the task

Symbol frequency

Java Core, Level 8, Lesson 11

Under discussion

I tried to resolve this task in this way bacause i could not find online other way

The program is started with one argument: the name of a file that contains text.
Calculate how often each symbol is encountered.
Sort the results by increasing ASCII code (read about it online).

Example:
','=44, 's'=115, 't'=116.

Display the sorted results:
[symbol1] frequency1
[symbol2] frequency2
Close the streams.

Example output:
, 19 - 7 f 361

Requirements:

You don't need to read anything from the console.
Create a stream to read from the file passed as the first argument of the main method.
You need to calculate the frequency of each symbol in the file and display the results.
The displayed results should be sorted by ascending ASCII code.
The stream used to read the file must be closed.

package com.codegym.task.task18.task1821; /* Symbol frequency */ import sun.misc.ASCIICaseInsensitiveComparator; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.IOException; import java.io.InputStream; import java.util.*; public class Solution { public static void main(String[] args) throws IOException { String a = args[0]; InputStream in = new FileInputStream(a); Map<Integer, Integer> map = new HashMap<>(); ArrayList<Character> ar = new ArrayList<>(); Map<Character, Integer> result = new HashMap<>(); int count = 1; for(int i = 0; i<in.available(); i++){ int x = in.read(); char y = (char)x; if(map.containsKey(y)){ map.replace(x, count+1); } else map.put(x, 1); } in.close(); Map<Integer, Integer> maps = new TreeMap<Integer, Integer>(map); for(Map.Entry<Integer, Integer> mapp : maps.entrySet()){ int p = mapp.getKey(); int s = mapp.getValue(); char k = (char)p; result.put(k, s); } for (Map.Entry<Character, Integer> mappp: result.entrySet()) { System.out.println(mappp.getKey() + " " + mappp.getValue()); } } }

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Andrew

Level 29 , Seattle, United States

20 March 2019, 17:38

A couple of things: 1. Since count always = 1, every time you replace an existing entry, the count will always be set to 2. 2. When you are searching your map for keys, you are searching for a char y but your map has int keys. I tested and confirmed that in this case, it doesn't convert char to int when it searches.

Map<Integer, Integer> map = new HashMap<>();
map.put(121, 1);

int x = 121;   // char 'y'
char y = (char)x;

System.out.println((map.containsKey(y)) ? "true" : "false");

Result is "false". 3. When you put entries from the TreeMap into a HashMap, it doesn't preserve their sorted order. 4. ArrayList ar is never used.