Question

JAVA Code:

Complete the program that reads from a text file and counts the occurrence of each letter of the English alphabet. The given code already opens a specified text file and reads in the text one line at a time to a temporary String. Your task is to go through that String and count the occurrence of the letters and then print out the final tally of each letter (i.e., how many 'a's?, how many 'b's?, etc.)

You can test your program with any text file; easiest if you put the text file in the same folder as your code. For example, if you have a file, book.txt, then you can simply type in book.txt when prompted by the program for the filename if the file is in the same folder as your program file.

Starter Code:

/*
* program that reads in a text file and counts the frequency of each letter
* displays the frequencies in descending order
*/

import java.util.*; //needed for Scanner
import java.io.*; //needed for File related classes
public class LetterCounter {
public static void main(String args[]) throws IOException{
Scanner keyboard = new Scanner(System.in); //Scanner to read in file name
System.out.println("Enter the name of the text file to read:");
String filename = keyboard.next();
  
//This String has all the letters of the alphabet
//You can use it to "look up" a character using alphabet.indexOf(...) to see what letter it is
//0 would indicate 'a', 1 for 'b', and so on. -1 would mean the character is not a letter
String alphabet = "abcdefghijklmnopqrstuvwxyz";
  
//TODO: create a way to keep track of the letter counts
//I recommend an array of 26 int values, one for each letter, so 0 would be for 'a', 1 for 'b', etc.
  
Scanner fileScan = new Scanner(new File(filename)); //another Scanner to open and read the file
//loop to read file line-by-line
while (fileScan.hasNext()) { //this will continue to the end of the file
String line = fileScan.nextLine(); //get the next line of text and store it in a temporary String
line = line.toLowerCase( ); // convert to lowercase
  
//TODO: count the letters in the current line
  

}
fileScan.close(); //done with file reading...close the Scanner so the file is "closed"
  
  
  
//print out frequencies
System.out.println("Letters - Frequencies in file:");
  
//TODO: print out all the letter counts
  
  
}
}

Answer 1

//Code to copy

/*
* program that reads in a text file and counts the frequency of each letter
* displays the frequencies in descending order
*/

import java.util.*; //needed for Scanner
import java.io.*; //needed for File related classes
public class LetterCounter {
public static void main(String args[]) throws IOException{
Scanner keyboard = new Scanner(System.in); //Scanner to read in file name
System.out.println("Enter the name of the text file to read:");
String filename = keyboard.next();

//This String has all the letters of the alphabet
//You can use it to "look up" a character using alphabet.indexOf(...) to see what letter it is
//0 would indicate 'a', 1 for 'b', and so on. -1 would mean the character is not a letter
String alphabet = "abcdefghijklmnopqrstuvwxyz";
int count [] = new int[26];
char mych [] = new char[26];
for(int i=0;i<26;i++)
mych[i]=(char)(i+97);
//I recommend an array of 26 int values, one for each letter, so 0 would be for 'a', 1 for 'b', etc.

Scanner fileScan = new Scanner(new File(filename)); //another Scanner to open and read the file
//loop to read file line-by-line
while (fileScan.hasNext()) { //this will continue to the end of the file
String line = fileScan.nextLine(); //get the next line of text and store it in a temporary String
line = line.toLowerCase( ); // convert to lowercase
for(int i=0;i<line.length();i++)
{
if(line.charAt(i)>=97 && line.charAt(i)<=122)
count[line.charAt(i)-97]+=1;
}
}
fileScan.close(); //done with file reading...close the Scanner so the file is "closed"

//print out frequencies
System.out.println("Letters - Frequencies in file:");
int temp;
char temp1;
//sorting
for (int i = 0; i < ( 26 - 1 ); i++)
{
for (int j = 0; j < 26 - i - 1; j++)
{
if (count[j] < count[j+1])
{
temp = count[j];
temp1=mych[j];
count[j] = count[j+1];
mych[j]=mych[j+1];
count[j+1] = temp;
mych[j+1]=temp1;
}
}
}
for(int i=0;i<26;i++)
{
System.out.println("Frequency of letter '"+(char)mych[i]+"' in file is: "+count[i]);
}

}
}

//Sample output

$C:\Windows system32\cmd.exe UsersIndrajeet Meena Desktop>javac LetterCounter.java :\Users\Indrajeet Meena\Desktop>Java LetterCounter nter the name of the text file to read: input.txt etters Frequencies in file: requency of lettertin file is: 5 requency of letterein file is: 4 requency of letterin file is: 4 requency of letterr in file is: 3 requency of letterj in file is: 2 requency of letterw in file is: 2 requency of lettera in file is: 1 requency of letterf in file is: 1 requency of letterk in file is: 1 requency of letternin file is: 1 requency of lettery in file is: 1 requency of letterb in file is: 0 requency of lettercin file is: 0 requency of letterd in file is: 0 requency of letterg in file is: 0 requency of letterh in file is: 0 requency of letteri in file is: 0 requency of letter1 in file is: 0 requency of letterin file is: 0 requency of lettero in file is: 0 requency of letterp in file is: 0 requency of lettersin file is: 0 requency of letterin file is: 0 requency of letterin file is: 0 requency of letterx in file is: 0 requency of letterz in file is: 0 UsersIndrajeet Meena Desktop>$

//Input file