Question

My calculation is not working properly. I can not see anything wrong with the code. Sometimes it does not calculate the score properly. Sometimes it does perfectly. I can not even understand when it does properly and when it does not do it properly.

Score calculation should be like this:

Ace can add to the total score either 1 or 11. If the score is higher than 21, then ace is calculated as 1; otherwise ace is 11.

Here is my code:

  // Updates the the value of the cards the player has in their hand
  int updateValueOfHand() {
    int result = 0;                             // it will be returned
    int ace = 0;                                // value of ace

    for (int i =0; i < playerHand.size(); i++)  // loop to see players hand
    {
      int cardValue;                            // card value of hand
      Card card=(Card)playerHand.get(i);        // check the card
      cardValue = card.getRank();
      if (cardValue == 1)                       // if card value is 1 (ace)
      {
        cardValue = 0;                         // assign to 0
        ace += 1;                              // ace is 1 (if there are 2 aces ace is 2 ...)
      }
      result = result + cardValue;             // result is card value (no ace)
    }
    //return result;
    println("Number of ace: " + ace);
    if (ace!=0)                                //if there is ace
    {
      for (int j=0; j<ace; j++)                // if there is more than 1 ace
      {
        if (result+11<=21) {                   // if result is <= 21 when you count ace as 11, then ace is 11
          result+=11;
        }        
        else {
          result+=1;                          // otherwise ace is 1
        }        
      }
    }
    return result;
  }

Answer 1

Consider a hand with one King and two Aces. This should be calculated as 10 + 1 + 1, since otherwise it would be greater than 21.

However, the program loops through each Ace, and:

// if result is <= 21 when you count ace as 11, then ace is 11

Since the King plus the first Ace counted as 11 is <= 21, the program chooses to count the first Ace as 11, but this in incorrect.

Here is one idea to fix it: In your first for loop, increase result by 1 for every Ace, then in your second for loop, increase result by 10 for every Ace as long as it stays <= 21.