WEBVTT 00:00.180 --> 00:07.350 Now, we have only used so survivors, we have only use integers for round numbers, but actually there 00:07.350 --> 00:09.090 are more data types you can use. 00:09.510 --> 00:12.830 So what kind of data that we will need in our program? 00:13.110 --> 00:16.180 The first foreign numbers, we have integers. 00:16.320 --> 00:22.250 Now, we also need let's say you want to store the value three point fourteen. 00:22.590 --> 00:26.050 You can put that in an integer as you try to do it. 00:26.640 --> 00:28.990 C is equal to three point fourteen. 00:29.250 --> 00:33.840 Well, this will be truncated and the real value will be three. 00:34.230 --> 00:36.280 OK, so how to store that? 00:36.300 --> 00:43.160 Well, you can use the float number so you can use float data type here. 00:43.500 --> 00:52.380 All you can use double the are roughly the same and you can store float number inside double and float 00:52.520 --> 00:52.780 that. 00:53.250 --> 00:55.970 So then of course you can do everything we did before. 00:55.980 --> 00:59.910 You can do a variation like plus minus multiply divided. 01:00.360 --> 01:03.030 You can combine variables, et cetera, et cetera. 01:03.390 --> 01:11.730 Another common data type that would be useful for us is the Boolean so that it will be bool and then 01:11.850 --> 01:16.890 name and a boolean can contain only two values. 01:17.130 --> 01:17.670 True. 01:18.890 --> 01:26.390 OK, you can see it turning blue or false, the booleans will be very useful when we try to test some 01:26.390 --> 01:30.090 conditions, for example, when we press a button in the car. 01:30.120 --> 01:33.430 We want to know where is the button priced or not. 01:33.800 --> 01:38.840 And in this case, we can use a Boolean to check that either it's true, it's false. 01:38.840 --> 01:43.160 And we are going to come back later to this when we see the conditions. 01:43.670 --> 01:51.650 And lastly, I'm going to show you the data type string, the string with an uppercase S. And this data 01:51.650 --> 01:55.100 type is actually not in the C and C++ language. 01:55.400 --> 01:57.290 This is specific to Arduino. 01:57.800 --> 02:00.950 So we string you can simply store some text. 02:01.130 --> 02:03.530 OK, so hello, Arduino. 02:03.890 --> 02:11.890 So when we have used that print and we've text before, actually that was a string. 02:11.900 --> 02:20.390 So it's like we could just do string name of the viable is equal to that piece of string and then I 02:20.390 --> 02:29.000 can print here and if you look at the same monitor, OK, and here it's interesting, we have an accurate 02:29.000 --> 02:33.920 away because we have tried to declare two variables with the same name. 02:33.990 --> 02:37.880 OK, this is in the same scope we're going to see later what is good. 02:38.150 --> 02:40.790 And we have two variables with the same thing. 02:40.790 --> 02:42.520 And this will produce an error. 02:42.860 --> 02:47.130 So we need to change here the variable to be unique. 02:47.180 --> 02:51.960 OK, so whenever you try to use to valuably with the same name, you will get an error. 02:53.220 --> 03:00.480 And now let's check what we have in the sale of print online and you will see hello and know can we 03:00.480 --> 03:03.890 are going to also practice more with strings later on in the schools. 03:03.900 --> 03:12.780 So you have integer foreign numbers, double for float numbers, but with a Kunoth million or booleans 03:12.780 --> 03:16.650 or true or false values and string for text. 03:17.160 --> 03:22.340 Now, one last thing to know about all of those data type is the range of the data. 03:23.130 --> 03:27.330 There is a limit actually to what you can store in those numbers. 03:27.410 --> 03:32.950 OK, so far in the jungling to just come to that later, that would be interesting. 03:32.970 --> 03:36.960 But for basically, you don't really need to worry about that. 03:37.360 --> 03:40.320 The value you can store is almost infinite. 03:40.320 --> 03:45.450 So no trouble about this boolean where there is no problem with it because you can just store value 03:45.450 --> 03:46.720 that are true or false. 03:46.750 --> 03:48.720 So there is no question about that. 03:49.140 --> 03:50.640 And train will. 03:50.640 --> 03:52.980 You can just do anything you want. 03:53.220 --> 03:55.470 The problem here comes with integers. 03:55.770 --> 04:00.830 Not an integer in order is stored in two debates. 04:01.410 --> 04:10.260 OK, and what does it mean for you practically is that you can store any value from minus thirty two 04:10.260 --> 04:17.940 thousand seven hundred sixty eight two plus thirty two thousand seven hundred sixty seven, if you try 04:17.950 --> 04:20.290 to start with a value that is bigger than that. 04:20.770 --> 04:23.730 Well, this will what we call overflow. 04:24.130 --> 04:26.010 So let's say you want to store. 04:26.310 --> 04:27.290 Let's make an example. 04:27.300 --> 04:36.330 Actually, I'm going to talk thirty two thousand seven hundred sixty eight, which is just above the 04:36.330 --> 04:36.840 limit. 04:37.110 --> 04:38.940 And let's print a. 04:44.670 --> 04:51.300 And you can see it's not that at all, it's minus thirty two thousand seven hundred sixty eight, which 04:51.300 --> 04:52.800 is the other opposite. 04:53.400 --> 04:58.110 So whenever you go below that value, you will actually come back to the maximum. 04:58.350 --> 05:02.370 And whenever you go after that value, you will come back to the minimum. 05:02.670 --> 05:04.260 This is what we call other flu. 05:04.440 --> 05:09.690 And this is a pretty common area you will get in your programs if, for example, you don't understand 05:09.690 --> 05:12.910 why you get some weird values with your integer numbers. 05:13.110 --> 05:14.780 Well, that may be because of debt. 05:15.090 --> 05:19.420 So when you use integer, make sure you don't use integer for high values. 05:19.670 --> 05:25.020 So whenever you need to use something more than, let's say, 10 or 20 thousands and you are not sure 05:25.020 --> 05:29.610 that you know the maximum, well, integer is not the best data type. 05:29.850 --> 05:31.140 How can you fix that? 05:31.440 --> 05:40.320 Well, you can use the data type long and a long data type is actually stored on four bytes, which 05:40.320 --> 05:47.110 means that you can go from two billion something to minus two billion, two plus two million. 05:47.670 --> 05:50.970 So we've long you should not have really any program. 05:51.420 --> 05:54.690 And the way to use long is the same as integer. 05:54.690 --> 05:59.730 So you just put any value like that. 05:59.740 --> 06:02.610 So you declare and you initialize it. 06:03.760 --> 06:09.430 I know if I print out here, this is four hundred thousand. 06:10.910 --> 06:13.790 Now, we should have the correct value. 06:13.860 --> 06:20.120 Yes, the four big integer numbers used long for smaller one use integer. 06:20.630 --> 06:25.480 All right, so now you have a global overview of what variables and why we need them. 06:25.790 --> 06:33.170 And just one more thing is that phone I've used later like a big to name valuables, but in any of your 06:33.170 --> 06:37.130 program and in the following of these goals, we will use meaningful names. 06:37.340 --> 06:38.300 It's very important. 06:38.300 --> 06:43.130 You put meaningful names for your valuables so you understand what it's OK. 06:43.130 --> 06:46.150 When I use a I don't know what is a OK. 06:46.400 --> 06:52.170 If you want to store, let's say, a user age, then simply name your valuable user age. 06:52.850 --> 06:55.610 OK, you can use the common keys. 06:55.760 --> 07:00.440 So you start with a lowercase and then for every new word you use uppercase. 07:00.890 --> 07:02.060 OK, with no space. 07:02.420 --> 07:04.550 So you use this convention for reliable. 07:04.880 --> 07:07.310 And this one for constants. 07:07.310 --> 07:11.840 So you can know what is the difference between a valuable you can change and a constant. 07:12.140 --> 07:14.540 So for example, you want to store a temperature. 07:14.540 --> 07:17.660 Let's, let's double temperature. 07:18.560 --> 07:22.520 OK, if you want to start a username then just name it. 07:24.070 --> 07:32.860 User name, and if you want to check that, that's senseor or any component is alive, then, for example, 07:32.860 --> 07:42.190 Boulle is alive, OK, using those variables, those names for the violence will make much more sense 07:42.370 --> 07:48.020 in your program and it will help you and other people read your code in the future. 07:48.580 --> 07:54.940 So to recap here, when you declare a viable in C and C++ with Arduino, you need to give it a type 07:55.150 --> 08:00.640 and to decide which type you should think about, what kind of data you want to store. 08:00.790 --> 08:07.590 And also, for example, when using wrong numbers, what is the maximum value you expect for the valuable?