CODEWITHSUNDEEP
javaarraysjava.util.scanner
user1020343
user1020343

Reputation: 11

Counting characters in a word

I want to create a program to output the number of occurrences of a letter in a word. Basicaly the output has to look like this:

Please enter a word—howdy
The word howdy has five characters.
What letter would you like to guess? (enter zero to quit) a
There are 0 A’s.
What letter would you like to guess? (enter zero to quit) b
There are 0 B’s.

This is what I got so far:

import java.util.Scanner;

public class LetterOccurence
{
  public static void main(String[]args)
  {
    Scanner input=new Scanner(System.in);
    String word;
    String letter;

    int letterNumber;

    boolean [] alphabet = new boolean [27];

    System.out.println("Please enter a word- ");
    word=input.next();

    System.out.println("The word  "+ word + " has " + word.length() + " letters\n");

    String lower = word.toLowerCase();

    for(letterNumber=0;letterNumber<lower.length();letterNumber++)
        {
            alphabet[lower.charAt(letterNumber) - 'a'] = true;
        }

    //do
    //{
    System.out.println("What letter would you like to guess? (enter 0 to quit) ");
    letter = input.next();

    if (alphabet[letter.charAt(0)-'a'] = true)
      {
        System.out.printf("There are %s's\n",letter.charAt(0));
      }
    else
      {
        System.out.printf("There are 0 %s's\n",letter.charAt(0));   
      } 

    //}while(Character.isLetter(letter.charAt(0))); 
  }
}

I am now stuck, any ideas on how to continue?

Upvotes: 1

Views: 2121

Answers (3)

Ted Hopp
Ted Hopp

Reputation: 234857

You don't want a boolean array for alphabet -- that only tells you what letters appear in the word, but not how many of each. Try this instead:

boolean [] alphabet = new boolean [27];
for(letterNumber=0;letterNumber<lower.length();letterNumber++)
{
    ++alphabet[lower.charAt(letterNumber) - 'a'];
}

Then later:

System.out.printf("There are %d %s's\n",alphabet[letter.charAt(0) - 'a'], letter.charAt(0));

Upvotes: 1

AusCBloke
AusCBloke

Reputation: 18532

For a start, booleans only hold a true or false value, you can't count with them. Rather than in your loop setting each element in the array that maps to a certain character to true, you could simply increment the counter.

In this case you're going to require an int as opposed to a boolean. And to print out the amount of occurrences for a specific letter, you obviously just print out the int value at that specific index of the array.

An alternative is also a Map<Character,Integer>, rather than calculating the index for specific chars in your array.

EDIT: As Dave mentioned, your if statement is also broken.

Upvotes: 2

Dave Newton
Dave Newton

Reputation: 160321

If nothing else, that if statement in your commented-out do/while is using a single = (assignment) instead of == (comparison).

All you really need to do is keep a single count per guess, initialize it to zero, and each time you encounter the guessed letter, increment it.

If you're trying to do all that work "up front" before guessing, then you don't really need a map of booleans, you need a map of ints, one per lower-case letter, initialized to zero, and incremented each time its corresponding letter is guessed.

You're very close.

Upvotes: 1

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