1 00:00:00,660 --> 00:00:00,960 All right. 2 00:00:00,990 --> 00:00:06,300 Welcome back to another lecture, we are now going to get into a new kind of piece of the course where 3 00:00:06,300 --> 00:00:08,730 we talk about abstract data types. 4 00:00:09,480 --> 00:00:16,540 So abstract data types are things that are going to enable us to bring abstract ideas into our programs. 5 00:00:16,560 --> 00:00:24,930 So when I say abstract, I mean things that are not as well defined like things that we've done so far. 6 00:00:25,230 --> 00:00:32,970 Functions, loops, variables of types that are integers and boolean things that you were just told 7 00:00:33,420 --> 00:00:34,890 how they work and what they do. 8 00:00:34,890 --> 00:00:38,850 And they're kind of part of the language and you were just learning to program with these building blocks. 9 00:00:39,420 --> 00:00:45,780 Now we're going to kind of create our own blocks, our own shapes, our own data types. 10 00:00:46,400 --> 00:00:53,700 This is going to enable us to solve much bigger problems and turn kind of real world issues and real 11 00:00:53,700 --> 00:00:56,550 world world things that we want to build into code. 12 00:00:58,320 --> 00:01:02,520 So up until this point, we've just been dealing with pre-existing data types. 13 00:01:02,530 --> 00:01:07,680 So you've been told what these data types are and what they do, like an integer or float, bool, char, 14 00:01:07,710 --> 00:01:09,330 etc. all those things. 15 00:01:10,290 --> 00:01:13,870 Now comes the time when we're going to make our own data types. 16 00:01:13,890 --> 00:01:15,480 And why would we want to do this? 17 00:01:15,510 --> 00:01:18,090 Well, it's because of what I was just talking about. 18 00:01:18,420 --> 00:01:21,810 We want to represent abstract ideas in code. 19 00:01:22,920 --> 00:01:28,680 A good example is the string data type that we've been using that is actually something that someone 20 00:01:28,680 --> 00:01:29,130 made. 21 00:01:29,130 --> 00:01:35,670 It wasn't originally like baked into the basic fundamental structure of the C++ language. 22 00:01:36,120 --> 00:01:43,230 It was kind of added on was created by someone that wanted to extend the functionality and make programming 23 00:01:43,230 --> 00:01:46,290 in C++ more powerful, more simple. 24 00:01:46,290 --> 00:01:51,390 You kind of keep adding things on to a language and it becomes more abstract. 25 00:01:51,390 --> 00:01:54,960 It becomes closer to spoken language or something. 26 00:01:54,960 --> 00:02:02,220 You know, we're able to kind of use small pieces of code that are very powerful and do a lot, whereas 27 00:02:02,220 --> 00:02:09,120 you used to have to write maybe 10 or even 100 times as much code as far as typing characters just to 28 00:02:09,120 --> 00:02:10,050 do the same thing. 29 00:02:11,660 --> 00:02:19,250 So the data types we create can be a lot more abstract and imaginative, so we're going to go ahead 30 00:02:19,250 --> 00:02:24,380 and look at some simple, maybe somewhat trivial, but just to get us to understand some simple examples. 31 00:02:25,520 --> 00:02:28,490 So let's think back to the string data type. 32 00:02:29,390 --> 00:02:31,880 It had a member function called length, right? 33 00:02:31,890 --> 00:02:35,570 We had to use the dot length to get the length right. 34 00:02:36,890 --> 00:02:39,980 So that gave us the length of the string, of course. 35 00:02:40,820 --> 00:02:45,610 So what if I told you to instead design a car data type? 36 00:02:45,680 --> 00:02:48,920 This may seem weird because you're like, Well, my car's a physical thing. 37 00:02:49,430 --> 00:02:50,890 You know, it's not like a code thing. 38 00:02:50,900 --> 00:02:52,300 A string was like a code thing. 39 00:02:52,310 --> 00:02:58,370 It's a virtual like digital data thing like the car's not that I can see a car, I can drive a car. 40 00:02:58,370 --> 00:02:59,420 You can touch the car well. 41 00:02:59,900 --> 00:03:03,830 We can represent the idea of what a car is in code. 42 00:03:04,340 --> 00:03:08,510 So that makes me then have another question for you. 43 00:03:08,520 --> 00:03:12,380 So what kind of information would be associated with that? 44 00:03:12,950 --> 00:03:20,720 And then more specifically, what type of member functions like this might you have for that car data 45 00:03:20,720 --> 00:03:21,020 type? 46 00:03:22,800 --> 00:03:27,240 So you could, of course, have a length function, I mean, a car has a length just like a string, 47 00:03:27,240 --> 00:03:27,600 right? 48 00:03:28,200 --> 00:03:32,460 But can you think of things that are a little more specific to cars? 49 00:03:33,630 --> 00:03:41,460 So if I said that this car could hold a collection of variables, so this car data type can hold variables 50 00:03:41,460 --> 00:03:48,090 of other types that you already know, like and charbel and string, what values would you have in these 51 00:03:48,090 --> 00:03:48,870 variables? 52 00:03:48,870 --> 00:03:49,950 What would they be? 53 00:03:49,950 --> 00:03:53,220 What variable names would you put for them? 54 00:03:54,000 --> 00:03:59,530 Let's say you had maybe like an integer, a float in a string or something like that. 55 00:03:59,550 --> 00:04:05,400 What would you put as the names for those if you were going to associate it as information that has 56 00:04:05,400 --> 00:04:06,540 to do with card? 57 00:04:08,920 --> 00:04:10,930 So let's think about the car data type. 58 00:04:11,980 --> 00:04:13,400 What about the price of the car? 59 00:04:13,420 --> 00:04:14,850 A car has the price right. 60 00:04:14,860 --> 00:04:20,800 You could make a price variable for this car data type if you made a price variable, what data type 61 00:04:20,800 --> 00:04:21,400 would that be? 62 00:04:21,430 --> 00:04:23,650 Would you make it an end or would you make it a float? 63 00:04:24,280 --> 00:04:25,870 What about the color of the car? 64 00:04:26,560 --> 00:04:27,850 Would you make that a string? 65 00:04:28,900 --> 00:04:34,750 So these are questions that you're going to need to answer when you're creating your own abstract data 66 00:04:34,750 --> 00:04:35,140 types. 67 00:04:37,190 --> 00:04:42,470 So the first thing that I'm going to discuss as far as implementing abstract data types is something 68 00:04:42,470 --> 00:04:43,670 called structs. 69 00:04:44,000 --> 00:04:50,180 So there's multiple ways to associate a collection of these variables that we're talking about that 70 00:04:50,180 --> 00:04:52,610 have to do with a type that you came up with. 71 00:04:54,010 --> 00:04:59,230 The first one that we go through is structs, it's kind of the most simple one, this was actually part 72 00:04:59,230 --> 00:05:03,190 of the sea language before C++ came around. 73 00:05:04,000 --> 00:05:14,990 So sea has struck, C++ has a lot more than what C++, but see kind of as far as the terms of abstraction 74 00:05:14,990 --> 00:05:16,440 and kind of stopped its structs. 75 00:05:18,520 --> 00:05:22,340 So here we have a struct in an example program. 76 00:05:22,360 --> 00:05:25,780 Nothing is happening in Maine, so it doesn't really do anything. 77 00:05:25,780 --> 00:05:28,510 But this is how you would declare a struct. 78 00:05:29,440 --> 00:05:34,330 And so a struct you can just think of as a structure of data. 79 00:05:35,200 --> 00:05:37,810 So we're saying, OK, we're going to have a structure. 80 00:05:37,810 --> 00:05:43,030 So it's kind of like, you know, a shape or a building or, you know, some type of structure. 81 00:05:43,300 --> 00:05:44,020 That's what it is. 82 00:05:44,020 --> 00:05:45,520 So we say struct for short. 83 00:05:46,300 --> 00:05:47,500 Here's what we call it. 84 00:05:47,500 --> 00:05:51,730 We call it car, and we're going to talk about naming conventions in a bit. 85 00:05:51,760 --> 00:05:55,600 You notice I have a lowercase right now, but that's not necessarily what we're going to do for our 86 00:05:55,600 --> 00:05:56,260 names. 87 00:05:56,920 --> 00:05:58,620 But I'm just keeping it kind of simple. 88 00:05:58,630 --> 00:06:01,660 You can do this, you can name it all lowercase car. 89 00:06:03,550 --> 00:06:07,750 And then we have some brackets, you know, we're very familiar with the brackets we use, the brackets 90 00:06:07,750 --> 00:06:09,040 for the functions, right? 91 00:06:09,040 --> 00:06:12,040 Like this main function, we use brackets for the F. 92 00:06:12,040 --> 00:06:17,050 We used brackets for the for in the while, right when we're defining a struct. 93 00:06:17,860 --> 00:06:20,890 You know, this is up here in global space. 94 00:06:20,900 --> 00:06:22,300 It's a global variable. 95 00:06:23,110 --> 00:06:25,030 It's accessible to main. 96 00:06:25,060 --> 00:06:31,870 It'll be accessible to the rest of the program if we continue to put other functions in between the 97 00:06:31,880 --> 00:06:32,920 struct in main. 98 00:06:33,520 --> 00:06:36,370 This is going to be accessible throughout the whole file. 99 00:06:37,690 --> 00:06:39,820 So what are we doing here? 100 00:06:40,090 --> 00:06:41,320 Let's take a closer look. 101 00:06:41,440 --> 00:06:44,230 So this struct has three member variables. 102 00:06:44,350 --> 00:06:51,850 You've heard me say member functions like dot length for the string that was a member function right 103 00:06:52,180 --> 00:06:56,560 of string, just like vector dot size, right? 104 00:06:56,710 --> 00:07:02,830 When you make a vector, let's say a vector and you call it my vector and you do my vector size, that 105 00:07:02,830 --> 00:07:05,260 dot size was a member function, remember? 106 00:07:06,390 --> 00:07:11,370 So this drug has three what we're calling member variables. 107 00:07:12,400 --> 00:07:16,990 And it's because they are associated, they are members of the Struct.. 108 00:07:18,110 --> 00:07:23,970 So these are price color and miles per gallon, which have just shortened to empty. 109 00:07:26,380 --> 00:07:30,850 So how do we access or use these member variables? 110 00:07:31,220 --> 00:07:33,440 You notice that they've been declared in here? 111 00:07:33,850 --> 00:07:40,040 So you're saying, OK, well, we have a car, this car has three different variables inside of it. 112 00:07:40,750 --> 00:07:43,300 It's got price, colour and miles per gallon. 113 00:07:44,580 --> 00:07:52,370 Kind of looks like this car is this big box and inside the box, we have, you know, three other small 114 00:07:52,370 --> 00:07:52,820 boxes. 115 00:07:52,820 --> 00:07:56,390 This can all store data, so let's say the main big boxes here. 116 00:07:56,390 --> 00:07:58,250 Car stores some data, right? 117 00:07:58,580 --> 00:07:59,480 What does it store? 118 00:07:59,510 --> 00:08:03,060 Well, it stores three other primitive data types. 119 00:08:03,090 --> 00:08:04,820 In fact, this is not primitive. 120 00:08:04,850 --> 00:08:07,670 The strings, not primitive, but the intent to float are. 121 00:08:08,720 --> 00:08:10,460 But it stores three data types, right? 122 00:08:10,490 --> 00:08:15,740 It doesn't they don't have to be primitive, they can be anything, you know, they could even be abstract 123 00:08:15,740 --> 00:08:16,600 data types in here. 124 00:08:16,610 --> 00:08:21,680 The point is the car just has three variables of various types in here. 125 00:08:22,580 --> 00:08:25,280 Each one of those variables has its own type two, right? 126 00:08:26,360 --> 00:08:30,710 So here we have car type and we have a price. 127 00:08:31,720 --> 00:08:37,600 Which is an entity we have color, which is a string type, and we have per gallon, which is a float 128 00:08:37,600 --> 00:08:37,870 type. 129 00:08:40,090 --> 00:08:46,230 So the weather we're going to access these member variables is just like the dot length and the dot 130 00:08:46,240 --> 00:08:49,060 size that I was talking about for those functions. 131 00:08:49,660 --> 00:08:57,220 You can do the same thing for the member variables, so you notice that I'm using Dot, the dot operator 132 00:08:57,220 --> 00:08:57,580 here. 133 00:08:58,150 --> 00:09:05,500 Before we do that, though, just like creating a variable of type int in here. 134 00:09:06,250 --> 00:09:13,540 And just like we might create an end inside of our main, we need to create a variable of type car. 135 00:09:14,920 --> 00:09:22,270 So notice that here we are declaring a local variable inside main of type car, just like we would do 136 00:09:22,270 --> 00:09:24,400 with one of these other types in Maine. 137 00:09:24,400 --> 00:09:29,560 We could, of course, say string color and then we could say color equals blue. 138 00:09:30,250 --> 00:09:36,640 But what we're doing here is we're saying, OK, I'm going to declare a variable of type car in Maine, 139 00:09:37,300 --> 00:09:40,600 and I'm giving that variable the name C here. 140 00:09:40,690 --> 00:09:44,170 So rather than like, you know, end my end, it's car. 141 00:09:44,390 --> 00:09:46,360 See, this is the type. 142 00:09:46,600 --> 00:09:47,920 This is the variable name. 143 00:09:49,000 --> 00:09:57,550 The way that we access the variables, and in this example, here I am assigning a value to it after 144 00:09:57,550 --> 00:09:58,300 accessing it. 145 00:09:58,630 --> 00:10:03,970 Accessing happens with the DOT, so we have see which is our variable name, right? 146 00:10:04,210 --> 00:10:05,990 This was a variable name for a car. 147 00:10:06,010 --> 00:10:08,530 It was C with an instance of a car. 148 00:10:09,610 --> 00:10:12,580 And we do see dot price. 149 00:10:13,630 --> 00:10:15,460 So this is the dot operator. 150 00:10:15,460 --> 00:10:17,170 It's similar to those member functions. 151 00:10:17,170 --> 00:10:21,820 We are accessing the variable car dot price. 152 00:10:22,390 --> 00:10:26,350 So imagine here when I say car, right? 153 00:10:26,440 --> 00:10:29,080 So that gives me this box, this big box. 154 00:10:30,390 --> 00:10:37,230 Then I say car dot, and then I have access to all three of these in here, and I say after the DOT, 155 00:10:37,230 --> 00:10:42,570 I put color that gives me access to this specific box inside of the car box. 156 00:10:43,290 --> 00:10:50,660 That's what you can imagine it as kind of as kind of a metaphor or analogy or something like that. 157 00:10:50,670 --> 00:10:55,890 So we use this dot here for all of the different variables and we're setting them. 158 00:10:56,490 --> 00:11:08,190 We now store the value 20000, the integer 20000 into the price member member where we're calling these 159 00:11:08,400 --> 00:11:09,450 member variables. 160 00:11:09,450 --> 00:11:17,130 So the integer twenty thousand is now getting stored and assigned to the price member. 161 00:11:18,210 --> 00:11:20,820 Next, we have these string blue. 162 00:11:21,200 --> 00:11:22,770 Remember, this is a string four color. 163 00:11:23,370 --> 00:11:31,560 The string blue gets assigned to the color member of the car variable that we made, and then the float 164 00:11:31,560 --> 00:11:42,480 22.5 gets assigned to the MPD miles per gallon float member of our car that we made, which was seen 165 00:11:43,230 --> 00:11:43,620 here. 166 00:11:43,620 --> 00:11:45,480 We're just printing those out. 167 00:11:45,660 --> 00:11:47,790 Once again, we need to access them, right? 168 00:11:47,790 --> 00:11:50,100 It does not matter that we're not assigning stuff. 169 00:11:50,400 --> 00:11:56,280 Even if we want to print it out, we're going to have to use a dot to get access to anything inside 170 00:11:56,280 --> 00:11:57,060 the struct. 171 00:11:57,630 --> 00:12:06,330 So here we print to the console the car's price, the car's color and the car's mpg. 172 00:12:09,490 --> 00:12:21,520 So I tried to be very kind of detailed in my explanation about this initial struct idea. 173 00:12:22,570 --> 00:12:26,080 So I'm hoping that we can go straight into a practice problem right away. 174 00:12:27,100 --> 00:12:32,620 So what I want you to attempt and I say attempt, you know, don't feel bad if you can't figure it out, 175 00:12:32,620 --> 00:12:36,100 but I would like you to try to make a program. 176 00:12:37,140 --> 00:12:43,860 And sorry, this kind of knot doesn't have correct grammar here, but make a program that asks a user 177 00:12:43,860 --> 00:12:46,700 for their name, age and blood type. 178 00:12:46,710 --> 00:12:48,570 So this is going to be like a patient. 179 00:12:48,610 --> 00:12:48,930 Right? 180 00:12:49,350 --> 00:12:53,520 So this information should be stored in a struct called patient. 181 00:12:55,810 --> 00:13:02,080 And then that struct is going to need the appropriate member variables, I just said that a patient 182 00:13:02,080 --> 00:13:05,600 needs a name and age and a blood type. 183 00:13:05,620 --> 00:13:06,040 Right? 184 00:13:07,150 --> 00:13:09,280 So remember what I just talked about. 185 00:13:09,370 --> 00:13:18,270 You can access these variables by using patient whatever the variable name is, right? 186 00:13:18,280 --> 00:13:20,080 So patient is the type. 187 00:13:20,800 --> 00:13:21,100 Right. 188 00:13:21,100 --> 00:13:26,780 So we're calling it patient, but let's say that you name the variable something else. 189 00:13:26,800 --> 00:13:28,560 That's what this really means here. 190 00:13:28,570 --> 00:13:30,520 So it's not going to be the word patient. 191 00:13:31,620 --> 00:13:37,230 Let's just say you call it patient in the variable name is like. 192 00:13:39,010 --> 00:13:40,810 I don't know pee or something like that. 193 00:13:40,870 --> 00:13:48,070 We put patient pee, you would do pee dot and then the member name, right, the member variable name 194 00:13:48,070 --> 00:13:51,850 to have access to that, even for storing input into them. 195 00:13:51,850 --> 00:13:57,920 So if you're reading input in from the console, from the user, which you know how to do. 196 00:13:59,080 --> 00:14:05,740 Remember that when you're doing that, you can act like this whole thing right here, let's say p dot, 197 00:14:06,010 --> 00:14:14,470 whatever variable name that is going to be the same thing as when you just read into another variable. 198 00:14:14,690 --> 00:14:17,140 Right, a normal local variable that you would have created. 199 00:14:17,410 --> 00:14:23,230 So just want to let you know that so your output should look like this, you should make it look exactly 200 00:14:23,230 --> 00:14:23,970 like this. 201 00:14:23,980 --> 00:14:26,050 Of course, this is the user's input. 202 00:14:26,050 --> 00:14:29,050 I'm putting my name and age and a blood type. 203 00:14:29,440 --> 00:14:32,590 You don't have to put these things to test. 204 00:14:32,600 --> 00:14:35,890 You can use whatever test data you'd like as the user. 205 00:14:36,220 --> 00:14:37,600 But this should be the same. 206 00:14:37,600 --> 00:14:40,170 It should say this, it should say. 207 00:14:40,180 --> 00:14:46,000 And then after you enter it, it should say patient colon and the name age, colon in the age and then 208 00:14:46,000 --> 00:14:47,800 blood type colon and the blood type. 209 00:14:49,400 --> 00:14:56,360 All right, so go ahead and pause the video, head to your favorite editor and try and figure this out 210 00:14:56,360 --> 00:15:00,380 for yourself, and then you can continue watching the lecture once you are done. 211 00:15:03,100 --> 00:15:08,110 OK, so what I'm going to do is go over this before I continue the rest of the lecture, so I'm going 212 00:15:08,110 --> 00:15:08,980 to go here. 213 00:15:10,250 --> 00:15:21,050 And what I'm going to do is I am going to go into this program, so I think I can move that simply because 214 00:15:21,050 --> 00:15:21,980 I already made that. 215 00:15:22,430 --> 00:15:25,520 So what I'm going to do is I'm actually going to make a. 216 00:15:26,620 --> 00:15:34,960 File on a call, it struck out CP, so it's going to be stretched us CP, what I'm going to do is include 217 00:15:34,960 --> 00:15:37,410 extreme as I'm going to need that for sure, right? 218 00:15:38,130 --> 00:15:45,430 And then what I'm going to do is, say, using name base study because I'm feeling lazy. 219 00:15:46,510 --> 00:15:48,140 OK, now it's time to make our struct. 220 00:15:48,160 --> 00:15:49,120 So what are we going to do? 221 00:15:49,270 --> 00:15:50,440 We're going to say struct. 222 00:15:51,490 --> 00:15:52,960 We're going to want to make a patient struct. 223 00:15:53,170 --> 00:16:00,580 But what I want to say right now is that C++ has some style guidelines for naming things and capitalization 224 00:16:00,580 --> 00:16:01,090 and all that. 225 00:16:01,340 --> 00:16:04,180 And so I'm actually going to put a capital p for patient. 226 00:16:05,020 --> 00:16:09,460 This is something we'll discuss in greater detail later on, but you need to make sure to follow the 227 00:16:09,460 --> 00:16:13,840 style guidelines because that's kind of important. 228 00:16:13,840 --> 00:16:15,670 People created these standards of style. 229 00:16:16,540 --> 00:16:18,460 So you should have it be capitalized. 230 00:16:18,460 --> 00:16:20,380 So I'm going to say struct patient. 231 00:16:20,680 --> 00:16:23,650 You don't have to, but you should say capital patient. 232 00:16:24,190 --> 00:16:28,650 What I'm going to do now is think about that blood type, the name the age. 233 00:16:28,660 --> 00:16:32,110 So I'm going to say that the name is going to be a string. 234 00:16:32,110 --> 00:16:38,090 So let's do string name and for age, because it's not going to be a float, write your whole number 235 00:16:38,090 --> 00:16:39,400 of years old. 236 00:16:39,970 --> 00:16:43,180 So then our blood type should also be a string. 237 00:16:43,180 --> 00:16:49,150 I would call it a cha, but we have a I think and B and then O and then a b, right? 238 00:16:49,160 --> 00:16:50,350 I think those are the four blood types. 239 00:16:50,350 --> 00:16:55,360 So since there's a B and that's two characters, I'm going to go ahead and call this the string as well. 240 00:16:55,840 --> 00:17:02,510 So I will say string blood type, and I'll just do some camel case right there for that. 241 00:17:02,530 --> 00:17:08,440 The capitalization of every kind of second word, you know, or subsequent word. 242 00:17:08,770 --> 00:17:11,290 So I'm going to go ahead and leave it at that. 243 00:17:11,980 --> 00:17:13,630 Don't forget the semicolon here. 244 00:17:13,810 --> 00:17:14,860 That's an important thing. 245 00:17:16,090 --> 00:17:17,430 So now I have my struct. 246 00:17:17,440 --> 00:17:25,300 What I'm going to do is make my main function and then I am actually going to read into these variables. 247 00:17:25,300 --> 00:17:27,100 So I will see out something first. 248 00:17:27,100 --> 00:17:37,600 I will say, you want to say, enter your name, age and blood type. 249 00:17:37,890 --> 00:17:38,830 Know for blood type. 250 00:17:39,100 --> 00:17:45,970 We have like a b o a b something like that. 251 00:17:46,870 --> 00:17:47,450 All right. 252 00:17:47,470 --> 00:17:52,390 So and then now I'm going to leave it at that and then I will see in two. 253 00:17:53,230 --> 00:17:57,040 I will say, Oh yeah, we got to make our looks. 254 00:17:57,050 --> 00:17:58,540 We got to make our struct right. 255 00:17:58,570 --> 00:18:01,780 So what I'm going to do is make a struct variable. 256 00:18:01,780 --> 00:18:05,680 So we're going to see type patient, right, because our struct is type patient. 257 00:18:06,190 --> 00:18:07,390 I'm going to call that P. 258 00:18:08,080 --> 00:18:11,760 Now what we can do is read into these variables by using the dot, right. 259 00:18:11,780 --> 00:18:14,740 So I'm going to do p dot name. 260 00:18:14,740 --> 00:18:15,850 So we're going to read into that. 261 00:18:16,270 --> 00:18:22,480 Then I'll do p that age or in into that and then I'll do P Dot blood type. 262 00:18:23,610 --> 00:18:30,210 All right, now, all we've got to do is print it out, so I'm going to see out and I'm going to say 263 00:18:31,320 --> 00:18:39,450 the name and then I'll put a little space here and I will say Peacock name to print that out. 264 00:18:40,410 --> 00:18:42,000 I do doing in line. 265 00:18:42,010 --> 00:18:43,380 I'll say, see out. 266 00:18:45,300 --> 00:18:54,900 Yeah, age and repeat what age in line, and then I will see out blood type. 267 00:18:56,250 --> 00:18:59,670 And this will be that blood type. 268 00:19:03,530 --> 00:19:08,390 And I'll do an airline and then just to return zero and finish that up right there. 269 00:19:08,690 --> 00:19:11,080 So that is all we should really need. 270 00:19:11,090 --> 00:19:14,150 So we're asking the user for the name, age and blood type. 271 00:19:14,160 --> 00:19:21,200 We specify this these options here, and then we go ahead and read all those in and then we print them 272 00:19:21,200 --> 00:19:23,300 out in an order that was shown. 273 00:19:23,570 --> 00:19:25,310 So let's go ahead and try and run this. 274 00:19:25,310 --> 00:19:28,840 So I'm going to say G-force Plus struck that CBP dash. 275 00:19:28,850 --> 00:19:36,410 Oh, and I'm actually going to call this uh, I think I, I remove my executable before. 276 00:19:36,410 --> 00:19:38,550 It doesn't really matter, but I'm to call it patient out. 277 00:19:38,570 --> 00:19:42,740 So I'm going to say G Plus Plus stretched out CBP and then Dash. 278 00:19:42,740 --> 00:19:44,950 Oh, and patient got out. 279 00:19:46,160 --> 00:19:47,060 All right, so it looks like that. 280 00:19:47,060 --> 00:19:48,980 Comp. OK, so let's go ahead and run it. 281 00:19:50,330 --> 00:20:00,230 So in a name, age, blood type, I'm going to say killing seven and a b, and there we see a printout. 282 00:20:00,380 --> 00:20:00,860 You can go ahead. 283 00:20:00,860 --> 00:20:08,750 And again, I'll just say in a, uh, five type O and then all prints out nicely. 284 00:20:09,500 --> 00:20:15,230 OK, so pretty simple exercise was really just to get you to make your first struct and start feeling 285 00:20:15,230 --> 00:20:17,730 a little bit comfortable with the syntax. 286 00:20:18,710 --> 00:20:20,810 So let's head back to the lecture. 287 00:20:23,740 --> 00:20:28,960 So some important final notes that I want to go over on strokes and abstract data types in general. 288 00:20:30,220 --> 00:20:31,810 Here we have a stark rectangle. 289 00:20:31,900 --> 00:20:35,650 It has on the same line being declared width and height. 290 00:20:35,680 --> 00:20:38,390 These are two variables we have and width and height. 291 00:20:38,410 --> 00:20:40,210 You can just put them on the same line. 292 00:20:40,210 --> 00:20:44,050 You not have to do int width, semicolon and then into height semicolon. 293 00:20:44,050 --> 00:20:46,120 On the next line, you can just put it all on one line. 294 00:20:46,330 --> 00:20:51,370 Not sure if I've gone over that syntax before, but if you have stuff of the same data type, you could 295 00:20:51,370 --> 00:20:57,340 just say and and then with height, something else, something else and else and so on, if they're 296 00:20:57,340 --> 00:20:58,120 all integers. 297 00:20:59,350 --> 00:21:04,270 So we have width and height and then I make a rectangle variable, right? 298 00:21:04,570 --> 00:21:05,860 So type rectangle. 299 00:21:07,200 --> 00:21:13,530 Notice the capitalization to for that, for our abstract data type name, and then I put a variable 300 00:21:13,530 --> 00:21:20,580 name R1 and I make another rectangle R2, I say R1 dot with has the value of five now and R2 Dot with 301 00:21:20,580 --> 00:21:21,660 has a value of five. 302 00:21:22,110 --> 00:21:23,070 Then I'm like, huh? 303 00:21:23,190 --> 00:21:26,280 They both have the with five, and I haven't said what the height is. 304 00:21:26,280 --> 00:21:28,410 They're pretty much the same thing, right? 305 00:21:28,770 --> 00:21:34,040 So can I say if R1 equals equals R2, then print out same? 306 00:21:34,590 --> 00:21:36,900 No, you cannot do this. 307 00:21:37,350 --> 00:21:44,280 You cannot compare structs to each other or any other abstract data types that we will be going over 308 00:21:44,280 --> 00:21:46,650 in the future to each other by default. 309 00:21:46,650 --> 00:21:47,310 Like this? 310 00:21:47,850 --> 00:21:52,890 You know how you can compare an integer to an integer in a string to a string and a chart to a char? 311 00:21:53,250 --> 00:21:54,480 That was fine, right? 312 00:21:54,900 --> 00:22:01,830 Let's just say you had it with equals five and with two equals five. 313 00:22:01,830 --> 00:22:03,120 Like two integers like that. 314 00:22:03,120 --> 00:22:07,500 And you said with two equals with one, that's fine. 315 00:22:08,010 --> 00:22:08,640 That's fine. 316 00:22:08,640 --> 00:22:10,120 C++ is OK with that. 317 00:22:10,560 --> 00:22:15,690 You cannot compare structs because they are more complex. 318 00:22:15,690 --> 00:22:19,350 They have these inner variables and it's a user defined type. 319 00:22:19,860 --> 00:22:31,070 C++ actually expects you to describe what this comparison really means in terms of your data type, 320 00:22:31,080 --> 00:22:33,930 so you have to kind of create a new. 321 00:22:34,960 --> 00:22:41,110 Equality operator and a new less than operator are greater than operators, so on and so forth. 322 00:22:41,530 --> 00:22:43,320 And we're not going to get into that quite yet. 323 00:22:43,370 --> 00:22:48,700 That's something that we're going to do with abstract data types pretty soon, not too far away. 324 00:22:48,790 --> 00:22:51,100 But, you know, we're a little bit away. 325 00:22:52,390 --> 00:22:57,490 Just want to let you know you can't do this in case you try this, you cannot compare two strikes directly 326 00:22:57,490 --> 00:23:04,030 with these operators that you've learned these kind of, you know, less than greater than all that 327 00:23:04,030 --> 00:23:04,350 stuff. 328 00:23:04,360 --> 00:23:07,060 So don't try and do that. 329 00:23:07,390 --> 00:23:10,420 Another thing is don't forget the semicolon. 330 00:23:10,420 --> 00:23:12,670 So this has a semicolon. 331 00:23:12,670 --> 00:23:15,130 After the brackets you notice, the other things you've done. 332 00:23:15,130 --> 00:23:16,120 Look at the F here. 333 00:23:17,050 --> 00:23:22,150 The if doesn't need a semicolon after the brackets, the loops don't need a semicolon after the brackets, 334 00:23:22,150 --> 00:23:22,480 right? 335 00:23:23,260 --> 00:23:28,960 Neither do functions, but the struct do need a semicolon after the brackets. 336 00:23:28,960 --> 00:23:30,510 So just remember that. 337 00:23:30,520 --> 00:23:30,880 All right. 338 00:23:32,470 --> 00:23:37,360 So with that, this kind of I think enough to not overload you. 339 00:23:37,390 --> 00:23:42,820 I don't want to go over too much in this lecture other than introduce you to the idea of an abstract 340 00:23:42,820 --> 00:23:49,600 data type and one of the ways that you can implement your own abstract data type, which is a struct. 341 00:23:49,990 --> 00:23:56,410 So with that, I will see you in the next lectures where we will continue on talking about abstract 342 00:23:56,410 --> 00:23:57,040 data types.