WEBVTT 00:01.090 --> 00:09.200 We're at the end in the sections we should be doing some practice now in concert with problem one. 00:09.240 --> 00:18.500 So write a program that takes a radius is input and calculates the diameter circumference in the area 00:18.890 --> 00:22.900 of the given circle using functions. 00:22.910 --> 00:33.530 So we'll be needing some functions and double for our type in each room have functions for the diameter 00:35.770 --> 00:36.700 and for 00:39.040 --> 00:40.140 radius 00:43.860 --> 00:48.260 in the center comes from us 00:57.600 --> 00:59.540 and area. 01:07.670 --> 01:09.230 So it's just right. 01:09.230 --> 01:19.000 The main function code for is say radius and see out 01:21.250 --> 01:27.070 please tear your radius circle 01:31.580 --> 01:36.680 C in the radius and see each 01:41.720 --> 01:42.560 diameter 01:45.110 --> 01:49.900 circle is. 01:50.150 --> 01:51.410 Call the function 01:57.080 --> 01:59.840 at and. 02:00.080 --> 02:04.340 Or the rest of it. 02:04.840 --> 02:09.700 And it's super cool. 02:09.940 --> 02:21.410 It's. 02:21.800 --> 02:25.200 It's finally the area 02:39.450 --> 02:45.570 that one thing will need is the constant 02:48.030 --> 02:54.560 in say double and PI B pt. 2. 02:54.570 --> 02:56.870 Calculate all these things. 02:57.060 --> 03:02.240 Point 1 4 1 9 is good enough. 03:02.240 --> 03:03.010 So nos. 03:03.020 --> 03:08.250 I'm creating this outside of the main function. 03:08.270 --> 03:15.740 This makes it so that's it's global to the entire program. 03:15.740 --> 03:19.160 And this is a constant not a variable. 03:19.160 --> 03:26.960 So this is OK to do so if this is a variable this would be bad but since it's a constant it's not ever 03:26.960 --> 03:28.270 going to change. 03:28.580 --> 03:30.670 It's not a problem. 03:30.750 --> 03:36.210 So now it's right the functions 03:48.440 --> 04:02.070 this so if you remember the diameter is really just two times that radius Sancy two point o time radius. 04:02.490 --> 04:18.060 And that's all there is for that on the circumference is two times the radius times Pi or so you get 04:18.060 --> 04:21.770 the circumference of the circle the outer edge of the circle. 04:22.290 --> 04:26.260 And finally the area is 04:30.380 --> 04:30.790 I 04:33.340 --> 04:35.390 times the radius square right. 04:38.400 --> 04:38.910 That's it. 04:39.760 --> 04:41.280 So it's run this 04:49.030 --> 04:49.880 time. 04:51.400 --> 05:00.760 Five say and diameter is 10 conferences three point four something. 05:01.090 --> 05:05.230 And the area is seventy eight point five three nights. 05:07.330 --> 05:24.320 Is just going over some simple return value and parameters and that's it so the next problem is write 05:24.330 --> 05:33.390 a function that gets an integer from the user and do all the appropriate error checking. 05:33.390 --> 05:44.330 So we've kind of already seen this before and let's just comment stuff. 05:45.390 --> 05:46.390 OK. 05:46.630 --> 05:51.730 So let's write a function or to name it. 05:54.640 --> 05:58.060 So it's going to turn an integer and C gets integer 06:02.070 --> 06:03.610 user and 06:06.260 --> 06:08.120 that's going to be the name of it. 06:09.470 --> 06:14.600 So we saw this before in the last section with looping. 06:14.900 --> 06:21.820 So it's really asked us to do is take all that and then put it into a function. 06:22.010 --> 06:31.320 So it's going to return an integer and there's going to be no parameters. 06:31.460 --> 06:40.280 So I told you we're going to be returning to input again and again and we're still going to see some 06:40.280 --> 06:45.410 more input examples in the next two maybe three sections. 06:45.470 --> 06:50.810 So let's just write that definition of get integer 06:53.440 --> 07:00.440 integer and user call that right. 07:01.080 --> 07:08.190 So if you remember it's just have a Boolean for if we failed. 07:08.380 --> 07:14.490 So if the user typed in something incorrectly we're going to set that boolean to true 07:17.010 --> 07:18.450 integer for the number. 07:18.480 --> 07:28.510 Remember we're in use the do while loop you while while there's a failure rate. 07:28.840 --> 07:30.420 So we want to keep doing. 07:30.510 --> 07:37.960 Want to keep prompting the user as long as there is a failure and we set the failure to be false. 07:38.790 --> 07:44.680 At the start because at the start of the loop there is no failure rate. 07:46.420 --> 07:51.290 He's chair integer 07:56.560 --> 07:58.850 mirror. 07:59.160 --> 08:05.720 If so if you remember if there there's a failure we say see and fail on it. 08:05.860 --> 08:15.130 Now evaluate to true if we are in the failure state and we have to clear that state and then ignore 08:15.850 --> 08:18.220 any of the harmful 08:21.010 --> 08:28.960 effects we probably need another fiery here counts. 08:29.350 --> 08:32.760 Nor shoppers 08:35.560 --> 08:39.380 sex it by the way. 08:39.410 --> 08:46.350 256 is just kind of arbitrary is really Nannar probably put it to maybe even higher. 08:46.390 --> 08:59.560 If I could and it ignores that many number of characters up until a new line in or is going to output 09:00.140 --> 09:01.220 as input air 09:03.890 --> 09:06.720 in or is it just please try it. 09:12.150 --> 09:16.810 And if the set the failure flag to be true. 09:20.750 --> 09:33.520 There was a failure in this case then we have to do is return the integer number and here in the main 09:33.520 --> 09:34.690 reason to say 09:37.380 --> 09:47.950 the number number is called to get ger for my user 09:50.810 --> 10:00.180 bat and we're going to print out the number and number you got us 10:04.200 --> 10:04.590 number 10:10.780 --> 10:13.400 so sag and Fred. 10:13.600 --> 10:16.260 So he says please try again. 10:16.440 --> 10:17.660 So it's wrong. 10:17.670 --> 10:20.750 Some random garbage that's wrong. 10:21.160 --> 10:23.760 And 10 you got the number 10. 10:24.040 --> 10:25.000 OK. 10:25.000 --> 10:30.910 So if you're wondering why I keep harping on this example of the input it's because I really don't need 10:31.510 --> 10:38.750 input in the next section which is finally where are you going to make the game. 10:39.010 --> 10:48.120 So and to do that we need to have proper input and you'll see exactly what I mean when we start our 10:48.120 --> 10:48.570 game. 10:48.660 --> 10:57.690 So I know it's been a bit of a slog to get through all these sections but next time we're going to finally 10:57.690 --> 10:58.510 make a game. 10:58.530 --> 11:04.310 And after after that we'll be making a lot more games more frequently. 11:04.320 --> 11:11.650 So so joining me in the next section and watch actually star start actually doing our projects.