WEBVTT 0 00:00.560 --> 00:02.900 Now let's move on to Hint 9. 1 00:03.050 --> 00:07.580 So we want to call calculate_score() at some point in our code, 2 00:07.580 --> 00:14.630 and if the computer or the user has a blackjack, or if the user's score is over 21, then the game 3 00:14.630 --> 00:15.560 is going to end. 4 00:15.800 --> 00:21.440 This might be a good time to start tidying up our code a little bit, because we've got our function 5 00:21.440 --> 00:25.340 over here, the calculate_score() function, 6 00:25.340 --> 00:29.870 and remember that you can only call a function after it's been declared. 7 00:29.870 --> 00:37.380 So for example, if I wanted to call this function over here, then I actually can't. I can't say, calculate_score() 8 00:37.380 --> 00:40.980 because it hasn't yet been declared. 9 00:40.980 --> 00:47.700 So instead what I'm going to do is I'm going to take this function, and I'm going to move it to where 10 00:47.700 --> 00:49.230 we dealt our cards. 11 00:49.620 --> 00:55.920 So now that I've moved my function to above the line where I want to call it, it's now become valid 12 00:55.920 --> 00:56.610 code. 13 00:56.610 --> 01:02.220 And this is the place where I want to call it, because it's only after I've dealt the user and the 14 01:02.220 --> 01:06.510 computer some cards can I actually calculate their scores. 15 01:06.540 --> 01:10.800 Firstly, I want to calculate the score using the user's cards. 16 01:10.800 --> 01:18.840 So this list of cards from the user gets passed into this function and uses all of the logic to output 17 01:18.840 --> 01:20.490 some sort of score. 18 01:20.740 --> 01:25.450 And then I'm going to store that score in a variable, which I'll call user_score. 19 01:25.780 --> 01:29.080 And I'm going to do the same thing for the computer. 20 01:29.080 --> 01:32.710 So computer score = calculate_score()... 21 01:32.710 --> 01:40.780 and remember it's always helpful to add a little bit of a Docstring to tell ourselves and other programmers 22 01:40.780 --> 01:42.220 what this function does. 23 01:42.220 --> 01:43.510 Let's quickly summarize it. 24 01:43.510 --> 01:53.060 So this function is going to, """Take a list of cards and return the score calculated from the cards.""" 25 01:54.440 --> 02:00.380 So now when I open that parentheses, I know that I probably have to pass in my list of cards in order 26 02:00.380 --> 02:01.880 to get back the score. 27 02:01.910 --> 02:05.180 And now we've got the user_score and the computer_score. 28 02:05.180 --> 02:08.720 So this score could equal 0 if they got a blackjack, 29 02:08.720 --> 02:14.450 or it could just simply be the value of the cards that they hold all added up together. 30 02:15.290 --> 02:22.700 Now that we've called calculate_score(), we also want to make sure that if the computer, or the user has 31 02:22.700 --> 02:29.000 a blackjack, or if the user scores over 21, then we have to end the game. 32 02:29.810 --> 02:31.700 Let's write our if statements. 33 02:31.700 --> 02:42.360 If the user_score is equal to 0, or the computer_score is equal to 0, or the user_score is greater 34 02:42.360 --> 02:47.610 than 21, then in this case we're going to tell the game to end. 35 02:47.610 --> 02:52.680 So we could create a new variable called is_game_over, 36 02:53.430 --> 02:56.460 and we start out with False of course, 37 02:56.460 --> 03:01.750 but then when this happens we're going to change that variable to True instead. 38 03:02.440 --> 03:03.880 Our is _game_over 39 03:03.880 --> 03:06.520 variable is just a simple boolean, 40 03:06.640 --> 03:08.440 It starts out as False, 41 03:08.440 --> 03:12.040 and when certain conditions are met, then we change it to True. 42 03:12.070 --> 03:17.740 Now at the moment our program is not finished, so it's not really obvious how we're going to be using 43 03:17.740 --> 03:24.100 this is_game_over variable, but we're setting ourselves up for the next steps. Now that we're tracking 44 03:24.100 --> 03:25.480 if the game should end, 45 03:25.510 --> 03:28.930 we can look at this value to determine what to do next. 46 03:28.930 --> 03:31.180 So that's Hint 9 completed. 47 03:31.180 --> 03:34.570 Let's test our code and see how everything works so far. 48 03:34.960 --> 03:41.200 I'm going to add some print statements here so that I can see what the user's cards are, and what the 49 03:41.200 --> 03:42.550 user's score is. 50 03:42.550 --> 03:49.000 Using an f-string I'm going to show, "Your cards," so the user's cards, and the "current score". 51 03:49.960 --> 03:54.350 And I'm also going to print the, "Computer's first card." 52 03:54.380 --> 03:57.800 Remember when I first explained the rules of Blackjack? 53 03:57.800 --> 04:05.600 The dealer will reveal their first card, so you get a little bit of a clue as to what kind of hand 54 04:05.600 --> 04:06.560 they might have. 55 04:07.250 --> 04:13.040 So in here, we're going to insert the computer's cards, and we're only going to pick out the first 56 04:13.040 --> 04:13.760 item. 57 04:13.760 --> 04:15.800 So the one at index 0, 58 04:15.800 --> 04:20.100 and we do that using a square bracket after the name of the list. 59 04:21.300 --> 04:24.000 Let me just change that typo there. 60 04:24.000 --> 04:29.460 And now we're ready to give this program a run to see how it works. 61 04:29.490 --> 04:38.730 Now we've got our first cards showing which is the user_cards, and it's a list of two cards, a 3 62 04:38.730 --> 04:39.750 and a 2. 63 04:39.750 --> 04:42.840 A 3 and 2 adds up, of course, to 5. 64 04:42.840 --> 04:46.320 So the current score for the user is 5. 65 04:46.500 --> 04:52.440 Next, it shows us the computer's first card, and that is a 4. 66 04:53.070 --> 05:00.510 Now we can be reasonably assured that our code is working, and it's a good idea to regularly test your 67 05:00.510 --> 05:04.890 code so that you don't wait until the end, when there are a lot of problems and you don't know which 68 05:04.890 --> 05:06.780 part of the code is responsible.