Would you like to inspect the original subtitles? These are the user uploaded subtitles that are being translated: 1 00:00:00,180 --> 00:00:03,300 All right guys, I've got a fun coding challenge for you today, 2 00:00:03,570 --> 00:00:06,450 and it is a problem called fizzbuzz. 3 00:00:06,960 --> 00:00:11,910 Now this is probably one of the most asked questions at interviews for 4 00:00:11,910 --> 00:00:14,910 programmers because it tests the way that you think, 5 00:00:15,150 --> 00:00:20,150 and it allows the interviewer to see how you use your logic to solve a problem. 6 00:00:21,840 --> 00:00:24,960 And the problem we're going to tackle is a children's game called 7 00:00:24,960 --> 00:00:29,850 Fizzbuzz. Last time I checked the programmatic solution was actually up on 8 00:00:29,850 --> 00:00:30,540 Wikipedia. 9 00:00:30,540 --> 00:00:34,920 So I recommend reading the Wikipedia article only after you've solved this 10 00:00:34,920 --> 00:00:38,280 Programming challenge. The rules of fizzbuzz are really simple. 11 00:00:38,910 --> 00:00:42,990 Basically, you have a bunch of kids who sit around in a circle and going 12 00:00:42,990 --> 00:00:46,680 clockwise. The first kid says 1, the second kid says 2. 13 00:00:47,100 --> 00:00:51,810 But then when a kid encounters a number that's fully divisible by three, 14 00:00:52,320 --> 00:00:55,920 then instead of saying that number, he's going to say Fizz. 15 00:00:57,180 --> 00:00:59,310 And when the number is divisible by five, 16 00:00:59,610 --> 00:01:02,220 instead of saying the number, they should say Buzz. 17 00:01:02,820 --> 00:01:06,900 And if the number is divisible by both three and five, for example, 15, 18 00:01:07,200 --> 00:01:08,940 then they should say Fizzbuzz. 19 00:01:09,420 --> 00:01:14,420 So your program is going to replicate this for all the numbers up to and 20 00:01:14,610 --> 00:01:18,840 including a hundred. To start off, it will probably look something like this. 21 00:01:18,900 --> 00:01:20,970 It's going to print one, and then on the next line 22 00:01:20,970 --> 00:01:23,130 it will print two and then fizz, 23 00:01:23,160 --> 00:01:27,030 because three is divisible by three. And then four, 24 00:01:27,210 --> 00:01:29,760 and then five is divisible by five so it's a buzz. 25 00:01:30,390 --> 00:01:34,980 And then six is fizz because it's divisible by three and so on and so forth. 26 00:01:35,460 --> 00:01:39,030 This is what your program has to do. Take a look at the instructions, 27 00:01:39,330 --> 00:01:42,150 make sure that you understand what it is that your program has to do 28 00:01:42,510 --> 00:01:44,880 and then pause the video and try to give this a go. 29 00:01:48,920 --> 00:01:52,760 All right. So the first thing we have to do is to create a range, right? 30 00:01:52,820 --> 00:01:57,820 So let's say that for number in range, and our range is between 1 and 100, 31 00:01:59,930 --> 00:02:02,120 so we have to include 101 in here. 32 00:02:02,840 --> 00:02:07,460 And what we want to do is we want to check whether if the number's divisible by 33 00:02:07,460 --> 00:02:09,140 three, divisible by five, 34 00:02:09,410 --> 00:02:12,920 or if it's divisible by both three and five. 35 00:02:13,760 --> 00:02:18,200 Now we could write our code by doing this in order, right? We could say 36 00:02:18,260 --> 00:02:22,370 if number % 3 is equal to zero, 37 00:02:22,580 --> 00:02:24,320 then it's divisible 38 00:02:25,700 --> 00:02:26,750 by three. 39 00:02:28,700 --> 00:02:32,090 So you might think that you could write the code like this, 40 00:02:32,390 --> 00:02:35,720 but there is a crucial problem in the logic here 41 00:02:36,140 --> 00:02:40,790 namely that we know that the if, elif, else statements will stop 42 00:02:41,090 --> 00:02:44,750 once it's found one statement that's true. For example, 43 00:02:44,990 --> 00:02:47,420 if we take the number to be 15, 44 00:02:47,870 --> 00:02:50,420 15 divided by three is equal to zero 45 00:02:50,780 --> 00:02:55,130 so it's going to carry out whatever instruction is inside this if statement 46 00:02:55,430 --> 00:02:58,490 and then it's going to be done with it. It's going to skip this one 47 00:02:58,670 --> 00:03:01,180 and crucially, it's going to skip this one 48 00:03:01,510 --> 00:03:06,510 which is what we really need. Instead of structuring our code like this, 49 00:03:06,880 --> 00:03:10,030 what you might have done and what you should've done is in fact, 50 00:03:10,030 --> 00:03:12,190 have this at the top. 51 00:03:12,550 --> 00:03:17,080 So first check if it's divisible by three and by five, 52 00:03:17,740 --> 00:03:19,240 and then if that is not true, 53 00:03:19,570 --> 00:03:24,100 then check to see if it's divisible by five and then divisible by three or the 54 00:03:24,100 --> 00:03:25,300 other option works as well. 55 00:03:25,300 --> 00:03:30,250 You could do it like this. Because these two have no overlap in terms of the 56 00:03:30,250 --> 00:03:32,320 results and then it doesn't really matter. 57 00:03:32,890 --> 00:03:37,180 So now we can finally write our code because we can say, well, 58 00:03:37,180 --> 00:03:41,530 if the number that we're currently encountering is divisible by both three and 59 00:03:41,530 --> 00:03:44,140 five, then we have to print Fizzbuzz. 60 00:03:46,900 --> 00:03:50,710 If it's only divisible by three, then we're going to print fizz. 61 00:03:52,510 --> 00:03:55,780 And if it's only divisible by five, then we're going to print buzz. 62 00:03:58,470 --> 00:03:59,160 All right. 63 00:03:59,160 --> 00:04:02,400 Now that still leaves the remaining numbers, right? 64 00:04:02,430 --> 00:04:03,810 Because the remaining numbers 65 00:04:03,840 --> 00:04:07,950 which don't fit any of the criteria should just be printed out as the number. 66 00:04:08,460 --> 00:04:13,140 We can catch that quite easily with an else statement that catches basically every 67 00:04:13,140 --> 00:04:16,770 other number, in which case, we're just going to print the number. 68 00:04:17,490 --> 00:04:20,310 So now, if I go ahead and run this code, 69 00:04:20,820 --> 00:04:25,260 then you can see that all the way from 1 to 100, 70 00:04:25,620 --> 00:04:29,220 it's been able to work out which ones are fizz, which ones are buzz, 71 00:04:29,280 --> 00:04:33,390 and which ones are fizzbuzz. How did you get on with it? 72 00:04:33,750 --> 00:04:38,340 If you got stuck or if you don't understand why this logic matters, 73 00:04:38,640 --> 00:04:42,720 then I want you to try both versions that I showed you and see it 74 00:04:42,720 --> 00:04:46,650 step-by-step using the Thonny program just as we did before. 75 00:04:47,790 --> 00:04:51,780 That way you can visualize what's actually happening in terms of the logic and 76 00:04:51,780 --> 00:04:55,950 how it's flowing from one step to the next, to the next. Now, 77 00:04:55,980 --> 00:04:59,970 once you've done that, then go back to your exercise and try to complete it. 78 00:05:00,240 --> 00:05:03,990 It's really, really important that you don't just say, "Oh yeah, I understand 79 00:05:03,990 --> 00:05:07,590 now." It's a really good idea to make sure that your code actually works at the 80 00:05:07,590 --> 00:05:11,760 end of the day and to write the code yourself. Today 81 00:05:11,760 --> 00:05:16,760 we've learned all about loops and we're going to apply it in our final project. 82 00:05:17,640 --> 00:05:20,520 So that's what's waiting up for you in the next lesson. 83 00:05:20,820 --> 00:05:22,230 So head over that once you're ready. 8243