while loop returns random number instead of the string

Question

I'm creating an application that gets input from input.txt and finds the most frequent characters and replaces them with * symbols. But the output.txt displays random numbers with * . So I have no idea what's gone wrong.

import java.io.*;

public class StringTest1 {
 public static void main(String[]args)


  throws IOException{

   FileReader in = null;
   FileWriter out = null;

   try {
      in = new FileReader("input.txt");
      out = new FileWriter("output.txt");

      int c;
      while ((c = in.read()) != -1) {
         String sen = Integer.toString(c);
         String str = sen.toLowerCase();
         int[] freq = new int[str.length()];
         char maxChar = str.charAt(0);
         int i, j, max;

         //Converts given string into character array
         char string[] = str.toCharArray();

         //Count each word in given string and store in array freq
         for(i = 0; i < string.length; i++) {
             freq[i] = 1;
             for(j = i+1; j < string.length; j++) {
                 if(string[i] == string[j] && string[i] != ' ' && string[i] != '0') {
                     freq[i]++;

                     //Set string[j] to 0 to avoid printing visited character
                     string[j] = '0';
                 }
             }
         }

         //Determine maximum occurring characters
         max = freq[0];
         for(i = 0; i <freq.length; i++) {

             //If max is less than frequency of a character
             //then, store frequency in max and corresponding character in maxChar
             if(max < freq[i]) {
                 max = freq[i];
                 maxChar = string[i];
             }
         }
         String maxLetter = Character.toString(maxChar);
         String line = str.replaceAll(maxLetter, "*");
    char[]ch = line.toCharArray();
    out.write(line);
      }
   }finally {
      if (in != null) {
         in.close();
      }
      if (out != null) {
         out.close();
      }
   }

*4*7**8*7*2*4*8***7*2*4*3*0*2*3*0***4**8*08*0***6**5*0*3**6**4**7**6**5*2*2*05*8*0***4**0*7**6*0**2*06*7**8*7*2*7*0**8*2*3*0***4**8*05***0***5*0*3**2**4*05**0*03*2*4*3*0*2*4*5*6*5*0*4*04**4*0**7*00**5*2*4*7*6*7*2*7*****0****7**4**4*0***0**6*2*0**4****03**4*7*09*09*05**0*03*0*06*5**8*5*2*2*7*00********2*2*4*00*8***2*06**5*02*0**5**2**4*05**0*03*2*4**5*02*2*06*00*8***2*04*05*8*0***4**0*7**6*0**0

But I expect it to be word with most repeated character changed to *.

The original text (input.txt)

Java JDBC JSP Servlets
Struts Hibernate java Web Services
Spring JSF JAVA
Threads JaVa Concurrent Programming
jAvA Hadoop Jdbc jsf
spring Jsf jdbc hibernate

score 2 · Answer 1 · answered May 15 '19 at 17:45

2

in.read() returns a single character, i.e. a char value, but as an int value to support the extra -1 to indicate end of stream.

Integer.toString(c) then converts that numeric value as a string.

The numeric value of the first character J is 74.

Replace Integer.toString(c) with Character.toString((char) c)

answered May 15 '19 at 17:45

Andreas

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You beat me to write this answer +1 – Frakcool May 15 '19 at 17:47
1

While you correctly identified part of the problem, your solution is wrong. Simply using `Character.toString((char) c)` will result in output where every character is turned into asterisks (basically giving "****************..."), since OP always only operates on one character at a time. OP needs to completely throw away and rewrite their code. – Max Vollmer May 15 '19 at 18:00
@MaxVollmer Very true. I was answering why the code was giving all numbers. I wasn't trying to re-write OP's code to do what OP wanted. Let OP learn by fixing the code one step at a time. This is the first step in that process. – Andreas May 15 '19 at 18:05

Max Vollmer · Answer 2 · 2019-05-15T18:04:26.690

You need a rubber duck, and you need to read this: What is a debugger and how can it help me diagnose problems?

You are reading each character individually with (c = in.read().

Then you convert the integer (ASCII) value of that character into a String, so for example the first character J, which has the ASCII value 74, is turned into the String "74".

Then you do some convoluted stuff on that String "74" and replace '7' with '*', giving you "*4".

You do that with every single character, thus creating the resulting output file full of numbers and *.

You need to completely rewrite your code. Here's my suggestion for a proper implementation:

Read the input file in full into one String.
Iterate over the characters in that String to find the character that occurs most often.
Replace that character in your String with asterisks.
Write the resulting String to your output file.

while loop returns random number instead of the string

2 Answers2