WEBVTT 0 00:00.170 --> 00:03.230 Now let's move on to Hint Number 10. 1 00:03.410 --> 00:08.660 It says that if the game has not ended, ask the user if they want to draw another card. 2 00:08.690 --> 00:13.550 If yes, then use the deal_card() function to add another card to the user_cards list, 3 00:13.580 --> 00:22.250 if no, then the game has again ended. Over here in the if statement, we can add an else, because if 4 00:22.250 --> 00:28.700 the game hasn't ended, as in they haven't gone over 21 or nobody's got a blackjack, then we're going 5 00:28.700 --> 00:32.120 to ask the user if they want to get another card. 6 00:32.120 --> 00:38.930 I'm going to use an input, and I'm going to ask the user to type 'y' to get another card, 7 00:38.930 --> 00:41.570 otherwise type 'n' to pass. 8 00:41.570 --> 00:48.080 And I'm going to save this input inside a variable which I'll call user_should_deal. 9 00:49.160 --> 00:55.280 Now we can check to see if this variable is equal to 'y', 10 00:55.430 --> 01:02.450 well, in that case, we're going to add another card to the user's card list by doing the same thing 11 01:02.450 --> 01:09.890 that we did in the beginning, where we dealt two cards to each player by saying usercards.append(), 12 01:10.160 --> 01:12.380 and inside the parentheses, 13 01:12.380 --> 01:16.880 the thing that we want to append is the output from deal_card(). 14 01:17.780 --> 01:21.520 So just a quick check to make sure you've got all the parentheses there. 15 01:21.520 --> 01:24.880 And then we're ready to address the else. 16 01:25.120 --> 01:29.590 If they didn't type 'y', then that means they don't want another card. 17 01:29.590 --> 01:32.620 Well then in this case, the game has again ended. 18 01:32.620 --> 01:36.220 So we can say is_game_over = True. 19 01:37.900 --> 01:39.820 Let's take a look at the next step. 20 01:39.820 --> 01:42.610 How can we get our game to repeat itself? 21 01:42.730 --> 01:48.960 So Hint Number 11 tells us that the score will need to be rechecked with every new card drawn, and 22 01:48.960 --> 01:53.430 the checks in Hint 9 need to be repeated until the game ends. 23 01:53.460 --> 01:59.850 Notice how we've got this, flag is_game_over, which is set to True whenever the game ends. 24 01:59.970 --> 02:07.290 It starts off being False, and what this means is we can actually create a while loop, which basically 25 02:07.290 --> 02:09.490 keeps on calculating the user_score, 26 02:09.490 --> 02:16.540 and the computer_score, makes all of these checks, which are in Hint 9, and then repeats itself 27 02:16.540 --> 02:18.610 until the game ends. 28 02:18.820 --> 02:20.470 Let's go ahead and do that. 29 02:20.740 --> 02:26.980 After all the initial setup, we're going to create a while loop, and the while loop is going to be 30 02:26.980 --> 02:30.100 active until the game is over. 31 02:30.100 --> 02:37.800 So we can say while not is_game_over, then go ahead and carry out all of these instructions. 32 02:37.800 --> 02:39.570 So calculate the user_score, 33 02:39.570 --> 02:41.430 calculate the computer_score, 34 02:41.430 --> 02:46.080 check that nobody's gone over 21 and nobody's gotten a blackjack, 35 02:46.080 --> 02:49.290 and if the user wants more cards, then they should, 36 02:49.290 --> 02:51.420 if they don't, then the game is over. 37 02:51.420 --> 02:55.110 So let's go ahead and run and test our code. 38 02:55.110 --> 03:02.450 You can see that the first two cards we get are 10 and 5, which makes up a score of 15. 39 03:02.450 --> 03:05.870 So 15 is kind of nowhere near 21, 40 03:05.870 --> 03:09.620 so let's go ahead and type 'y' to get another card. 41 03:09.620 --> 03:12.620 You can see that our while loop is active. 42 03:12.620 --> 03:16.460 And it goes back to getting another card. 43 03:17.120 --> 03:22.730 And we end up with 10, 5, and 10, which unfortunately means that we're over 21, 44 03:22.730 --> 03:24.270 and so we lose. 45 03:24.270 --> 03:30.090 But if I tried this and I typed 'n', then you can see the game ends immediately. 46 03:30.900 --> 03:32.850 That worked perfectly. 47 03:33.000 --> 03:36.360 So now let's go back and tackle the next part. 48 03:36.390 --> 03:41.100 Hint number 12 says once the user is done, it's time to let the computer play. 49 03:41.130 --> 03:46.410 The computer should keep drawing cards as long as it has a score less than 17. 50 03:46.890 --> 03:52.910 So the while loop is responsible for dealing with when the user wants to keep drawing cards, 51 03:52.910 --> 04:00.230 but once that's done, then we can tackle Hint Number 12, which is how does the computer actually play? 52 04:00.230 --> 04:02.300 What is its strategy? 53 04:02.330 --> 04:09.380 Well, we know that the computer has to keep drawing cards as long as it has a score of less than 17, 54 04:09.380 --> 04:15.440 but of course, 0 which represents a blackjack, is also less than 17, 55 04:15.440 --> 04:19.640 but we don't want it to draw a card if it has a blackjack. 56 04:20.030 --> 04:30.650 We can represent this logic using a while loop, while the computer_score is not equal to 0, and 57 04:30.650 --> 04:38.630 the computer_score is less than 17, then in this case we want to keep drawing cards. 58 04:38.810 --> 04:46.460 We're going to take the computer's cards, and we're going to use the append to add a card by dealing 59 04:46.460 --> 04:48.410 another card to the computer. 60 04:48.860 --> 04:54.470 And then we're going to recalculate the computer_score so that it updates, 61 04:54.470 --> 04:58.850 and this while loop is evaluated on the latest score. 62 04:58.940 --> 05:04.960 So the computer_score is going to equal calculate_score() using the computer_cards, 63 05:05.050 --> 05:12.340 and that means that the updated computer_score is equal to the return value from calculate_score(). 64 05:12.370 --> 05:18.100 Now one thing you'll notice here is that we've got a warning underline for the computer_score, 65 05:18.100 --> 05:24.400 and when we hover underneath it it says the "Name 'computer_score' can be undefined." 66 05:24.400 --> 05:26.170 So what does it mean here? 67 05:26.200 --> 05:32.310 Well notice that we first define this variable computer_score inside this other while loop. 68 05:32.340 --> 05:36.480 Now we're hoping that hopefully this happens first, 69 05:36.480 --> 05:41.250 and by the time we reach Line 46, we already have a value for computer_score, 70 05:41.250 --> 05:44.550 and this will happen in pretty much all cases. 71 05:44.550 --> 05:51.840 But just in case there is a glitch, and there is no value for computer_score, or even in the case where 72 05:51.840 --> 05:57.520 this entire while loop is skipped, then this computer_score will be equal to undefined. 73 05:57.520 --> 05:59.230 It won't actually exist. 74 05:59.230 --> 06:06.400 That variable won't have been created for us to check whether or not if it equals to 0, or if it's 75 06:06.400 --> 06:08.440 greater or less than 17. 76 06:08.440 --> 06:10.600 So how can we fix this? 77 06:10.600 --> 06:16.840 Well, right up here where we've got our user_cards and computer_cards where we defined all of our empty 78 06:16.840 --> 06:22.290 variables, we should go ahead and define this computer_score right here. 79 06:22.320 --> 06:27.750 Now we can't set it to equal 0 by default, because that means blackjack in our game. 80 06:27.750 --> 06:34.410 So let's set it to a number that we, when we test our code, will know for sure there is an issue. 81 06:34.410 --> 06:36.930 Let's set it to a negative number. 82 06:36.930 --> 06:45.960 So notice how as soon as I've got that variable defined somewhere outside of the while loop, this warning 83 06:45.960 --> 06:53.610 now goes away and it will always have a value, even if it is a value that signifies there's something 84 06:53.610 --> 06:54.900 wrong with our code. 85 06:55.140 --> 06:57.780 And that will help us debug as well. 86 06:58.440 --> 07:03.720 Now you'll notice that we've actually got a similar situation with the user_score. 87 07:03.720 --> 07:10.680 The user_score is only defined inside this while loop, so it's created as a variable here and only 88 07:10.680 --> 07:12.330 assigned as a variable here. 89 07:12.330 --> 07:17.490 And in future if we want to use it, we also need to do the same thing. 90 07:17.490 --> 07:23.130 So let's just also create a user_score and set it to -1 as well. 91 07:24.060 --> 07:31.170 So now that we've completed Hint number 12, it's time to move on to the next video where we're going 92 07:31.170 --> 07:33.300 to go through the final hints.