I still don't understand the FOR loop?

Question

Can you explain the formatting and logic of the FOR loop a little more, it isn't sinking in for me. This challenge has thoroughly stumped me.

Thank You!!!

ScrabblePlayer.java

public class ScrabblePlayer {
  private String mHand;

  public ScrabblePlayer() {
    mHand = "";
  }

  public String getHand() {
   return mHand;
  }

  public void addTile(char tile) {
    // Adds the tile to the hand of the player
    mHand += tile;
  }

  public boolean hasTile(char tile) {
   return mHand.indexOf(tile) > -1;
  }

   public String getTileCount() 
   { int counter = 0; 
     for (char letter : mHand.toCharArray()) 
      { if (mHand.indexOf(letter) >= 0) 
          { 
            counter++; 
          } 

      }
    return counter;
   }

Answer 1 · 2015-01-18T17:55:46Z

January 18, 2015 5:55pm

Benyam;

Welcome to Treehouse! It is great you are asking questions early on as many of these early subjects are built upon later and the theory/logic behind them caries over into most programming languages.

Let's take a look at a different example of a For Each loop written in English and see if it helps...

Imagine that we have a group of Students, say here at Treehouse. The Treehouse staff wants to know how many student's are from the United States. Prior to computers we would sit down with all of the enrollment forms and search each form, right? We can do that with code using a For Each loop. In English we would say

For each student in the entire group of students do something, in this case look to see their country of origin.

The computer then will look through the group of students, look at each student and if they are from the United States increase a counter, for example, and then report back (return) the total number of students from the US.

Similarly, for the challenge we want to make a function, in this case called getTileCount() that will look at each tile in our group of tiles, or hand and then return that number. So if our hand has eight tiles with "A C D N N Q O O" and we wanted to know the number of "N" tiles we have, it will loop through each tile and when it finds a matching tile it will increase the counter by 1 and ultimately return the number 2. If we search for an "E" tile, we should expect to get a zero back with the above hand.

Does that make any sense in terms of the logic behind a For Each Loop?

For our challenge the general formatting we are needing to use is, without giving away the entire challenge:

public int getTileCount(char tileToFind) {
    int tileCount = 0;
    for ( /* looping through each tile */ ) {
         if ( /* a tile equals another tile */ ) {
          // do something magical 
        }
    }
    return tileCount;
}

Post back if you are still stuck on the challenge, or rewatch the video for more specifics on formatting.

Happy coding,

Ken

Answer 2 · 2015-01-18T23:07:44Z

January 18, 2015 11:07pm

You should check to see if the letter passed in to the method is equal to the character in your current loop, and only then increment.

Make sense?

Hope it helps!

Answer 3 · 2015-01-19T03:28:47Z

January 19, 2015 3:28am

Benyam;

Let's dive a little deeper into this challenge, you are very close I think, just some syntax issues which come with experience and practice. The challenge asks us:

So back to that ScrabblePlayer. I found that it's not enough to know if they just have a tile of a specific character. We need to know how many they actually have. Can you please add a method called getTileCount that uses the for each loop you just learned to loop through the characters and increment a counter if it matches? Return the count, please, thanks!

Like I said, it looks like you are on the right path, so let's see where we can tweak your code.

Your_code.java

  public int .getTileCount(char tileToFind)

{
    int tileCount = 0;
    for (char tileToFind: mHand.toCharArray())
    {
      if (mHand.indexOf(tileToFind) >= 0)
      {
        tileCount++;
      }
    }
    return tileCount;
  }

In your method definition you have a period preceding the name. You want to remove that and make it simply getTileCount. That causes a dereferencing error.
In your for statement, you already have declared the tileToFind variable inside the method definition, so that is causing an error. So you would want to create another variable, say searchingTile that is also of the type char.
In your if statement, you should be checking to see if the searchingTile is equal to the tileToFind In this usage we can check if the two are equal with the operator ==.

If we put all the pieces together we would wind up with something similar to:

public int getTileCount(char tileToFind) {
    int tileCount = 0;
    for (char searchingTile : mHand.toCharArray()) {
      if (searchingTile == tileToFind) {
        tileCount++;
      }
    }
    return tileCount;
}

I hope this helps more than causes confusion and while some of this is syntax related knowledge that comes through practice, if you still don't have a good grasp on what the above code is doing I would highly encourage you to watch the video(s) again or ask additional questions as loops are an important part of programming.

Happy coding,

Ken

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Benyam Ephrem

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I still don't understand the FOR loop?

3 Answers

Ken Alger

Ken Alger

Benyam Ephrem

Benyam Ephrem

Craig Dennis

Craig Dennis

Benyam Ephrem

Benyam Ephrem

Ken Alger

Ken Alger

Benyam Ephrem

Benyam Ephrem