Counting vowles in a collection of String objects

[sunde887]

I am working on an exercise in Thinking in java 4th edition, I have an idea of how to do it, but I am not sure how to do it the way the book specifies.
the question is:

Create a set of vowels. working from uniquewords.java, count and display the number of vowels in each input word and also display the total number of vowels in the input file:

the code for uniquewords.java is:

import java.util.*;
import net.mindview.util.*;

public class UniqueWords{
	public static void main(String[] args){
		Set<String> words = new TreeSet<String>(new TextFile("SetOperations.java", "\\W+"));
		System.out.println(words);
	}
}

it works correctly, lists all the words in a file named output.java and they are stored in the words treeset.

I am a little confused still with all the collection types, and I am still trying to figure them all out.

Here is my thought:

public static int countString(String str)
{
  int count = 0;
  for(int i = 0; i < str.length(); i++) 
  {
    switch(str.charAt(i)){
      case 'a':
      case 'A':
      case 'e':
      case 'E':
      case 'i':
      case 'I':
      case 'o':
      case 'O':
      case 'u':
      case 'U':
          count += 1;
      default:
          count;
       }
    }
return count;
}

then simply loop through the treeSet containing the words in a file applying each i to this new function. However, the book mentions using a Set of vowels, and Im not sure how I would implement them, also, would it be smarter to use an iterator to go through the treeSet? I am still a little weak with iterators as well.

Also, I can easily figure out the vowel per word by creating a new set if Integers and storing the value of countVowels each word in the new set, is the correct way to think?

[user0]

Hi sunde - if you are required to create a set of vowels, you can do so using the following contrustructor:

Set<Character> vowels = new TreeSet<Character>();
vowels.add('a');
vowels.add('A');

After that you can have two counters: one to count vowels in each word, and one to count total vowels. You can use a for each loop to get each string word from your set and use the contains method of the Set object:

for(String s: words) {
  for(int i = 0; i < s.length(); i++) {
      if(vowels.contains(s.charAt(i)))  {
         count something;
      }
  }
  count something;
}

Just an idea, hope it helps :)
Best,

[charleyjoyce]

also display the total number of vowels in the input file:

you can also read the whole file (if its not big) , and do this, assuming myString is the whole file already stored in a string.

        String myString = "The quick brown fox jumped over the lazy dog";
        int totalLen = myString.length();
        System.out.println ("Total vowels: " + ( totalLen - myString.replaceAll("[aeiouAEIOU]","").length() ) );

[Fubarable]

I have to wonder just what TextFile is? It must extend some Collection of some sort, perhaps an ArrayList.

[sunde887]

The textfile item is something the book creator created, he moves a bit ahead of what has been discusses so far. I have another question, if I want to use an iterator I am wondering if this is the correct method:

Iterator<String> it = ts.iterator();

while(it.hasNext()){
  String p = it.next();
  for(int i = 0; i < p.length(); i++){
    count collection items

Would this work? Also, if it is, a newly initiatied iterator, does it start at the 0 item in the list?

Thanks very much for the help so far.