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Javascript Help please!!

Hey all! I am having some trouble with my program for blackjack; my variables a,b,c and d will not store values from randomCard ( I use them later in the code to print out a card image on the screen). Does anyone see anything I might be overlooking? (randomCard DOES get a value from Deal(), which is a random number generator, I know this because randomC() utilizes randomCard).

Thanks for your time!

Code:



function NewGame(){

                player.length = 0;

                dealer.length = 0;

                playerTotal = 0;

                dealerTotal = 0;

                

                

                randomCard = Deal();

                a = randomCard;

                player [0] = randomC();



                

                randomCard = Deal();

                b = randomCard;

                player [1] = randomC();



                

                randomCard = Deal();

                c = randomCard;                

                dealer[0] = randomC();



                

                randomCard = Deal();

                d = randomCard;                

                dealer[1] = randomC();



                

                playerTotal = player [0] + player [1];

                dealerTotal = dealer [0] + dealer [1];

                document.form.player.value = playerTotal;

                document.form.dealer.value = dealerTotal;

I am putting the variables in the code shown below, if I enter a [0] or [1] the correct image shows up, but I need it to coincide with the the random variable instead of 0 and 1.

Code:

 <form NAME="form">

      <table height="165">

        <tr>

          <td height="137"><table width="814">

            <tr>

              <td><script>document.write('<img alt="random image" src="' + playerC[a] + '"/>');</script>

                <script>document.write('<img alt="random image" src="' + playerC[b] + '"/>');</script></td>

              <td><script>document.write('<img alt="random image" src="' + playerC[c] + '"/>');</script>

                <script>document.write('<img alt="random image" src="' + playerC[d] + '"/>');</script></td>

            </tr>

This makes NO SENSE at all:

Code:

                randomCard = Deal();

                a = randomCard;

                player [0] = randomC();

You get a randomCard. Fine. Then, for some weird reason, you assign it to the variable a

Why didn't you simply code a = Deal();?

But then you set player[0] to the result of calling the function randomC()!

WHY???

*APPARENTLY* you have a Deal( ) function that returns one random card. That's great. But then why do you have *ANOTHER* function randomC() that does the same thing????

On top of that, you get the score for the player by adding player[0] and player[1]. But why in the world would *THAT* score match the sum of the values of a and b??? Except by the wildest coincidence?

*********

In your second post, you show this:

Code:

document.write('<img alt="random image" src="' + playerC[a] + '"/>');

Now, all of a sudden, you have introduced the array playerC[].

Where did *THAT* come from?

In the prior code, you had player[0] and player[1], but you certainly didn't have any playerC[ ].

On top of everything else, document.write is badly obsolete and you should *NOT* be using it.

Deal() returns a value 0-51.
randomC() takes the RANDOMCARD and assigns it a card VALUE based on a case switch statement.

playerC[] are the cards, I have an array set up with 0-51 assigning a different card in the deck.

a & randomCard must be equal numbers so I assign the correct card, that is why I do not simply code a = Deal().

If document.write is so obsolete why not inform me of the appropriate code?

Thank you, I think.

Okay...begins to make more sense.

Your playerC is fine, though I would have used a more descriptive name. After all, you use those images for the dealer's cards, as well. Maybe cardImage[ ]?

But that's quibbling.

Quote:

randomC() takes the RANDOMCARD and assigns it a card VALUE based on a case switch statement.

Bad design. (Also misleading name.)

I would have written it as

Code:

function cardValue( card )

{

    ...

}

NEVER depend upon passing global variables around from function to function if you can help it!

If you were going to do that, you could have had Deal( ) set a global variable with the card's value. But even that is bad design.

*********

In place of document.write, you should use DOM methods.

For example:

Code:

              <td><img id="PC1" alt="player card 1"/></td>

              <td><img id="PC2" alt="player card 2"/></td>

              <td><img id="DC1" alt="dealer card 1"/></td>

              <td><img id="DC2" alt="dealer card 2"/></td>



....



<script type="text/javascript">

function dealTo( whom, imagePrefix )

{

    var total = 0;

    for ( var c = 0; c <= 1; ++c )

    {

        var card = Deal();

        total += cardValue( card );

        document.getElementById( imagePrefix + (c+1) ).src = playerC[card]; // I'd still rename playerC

        whom[c] = card;

    }

    return total;

}



function newGame( )

{

    playerCards = [];

    dealerCards = []; // better than setting length to zero...start with clean array



    playerTotal = dealTo( playerCards, "PC" );

    dealerTotal = dealTo( dealerCards, "DC" );

}

... other code ...

</script>

Yes, you should put the JS code *AFTER* all the HTML, just before the </body> tag.

By the by, there is no need for a switch( ) in your cardValue( ) function (what you were calling playerC( ).

Assuming that 0-12 are the Ace through King of Clubs, 13-25 are Ace through King of Diamonds, etc.:

Code:

function cardValue( card )

{

    card %= 13; // reduce to 0 through 12

    if ( card >= 10 ) { return 10; } /* J, Q, K */

    if ( card == 0 ) { return 11; } /* Ace */

    return card+1; // all other cards

}

If you use some other numbering system for the card images, you can still do it without switch( ), almost surely.

Oh...and named <form>s are also obsolete. Give the form an ID, instead, and then use

Code:

var form = document.getElementById("theForm");

or similar to refer to it.

Thank you so very much for your help! This cleared up a lot and I have the images showing with appropriate values. :thumbsup: