1 00:00:08,790 --> 00:00:11,670 So this lecture is really, an opportunity for us to 2 00:00:11,670 --> 00:00:15,350 walk through the big ideas, that you should have learned 3 00:00:15,350 --> 00:00:18,990 over the course of this Coursera course, to make sure, 4 00:00:18,990 --> 00:00:22,860 you've got the big concepts before you take the final exam. 5 00:00:22,860 --> 00:00:27,830 So these are not in-lecture quizzes, because these are serious. 6 00:00:27,830 --> 00:00:30,810 They're not intended to just be funny, well, 7 00:00:30,810 --> 00:00:33,260 as I've said before like I think is funny. 8 00:00:33,260 --> 00:00:33,710 So, 9 00:00:33,710 --> 00:00:36,360 really these are questions for you to reflect 10 00:00:36,360 --> 00:00:39,270 on, how well you think you understand a 11 00:00:39,270 --> 00:00:41,510 set of topics that I'm going to provide 12 00:00:41,510 --> 00:00:44,610 to you over the course of this Powerpoint show. 13 00:00:44,610 --> 00:00:50,270 So, for all of these questions, you should think about on a scale of 14 00:00:50,270 --> 00:00:55,690 none to excellent, how well you understand that particular topic. 15 00:00:58,000 --> 00:01:01,880 For example, for this first one, do you understand the difference 16 00:01:01,880 --> 00:01:07,150 between what variables and fields are, for and what methods are for? 17 00:01:07,150 --> 00:01:12,510 So this comes back to the core idea, behind object oriented programming. 18 00:01:12,510 --> 00:01:17,840 Where we store data, state information in fields and then 19 00:01:17,840 --> 00:01:23,740 we provide behavior, from classes by implementing methods for those classes. 20 00:01:23,740 --> 00:01:28,760 So that's sort of the core idea here, the difference between the data and the 21 00:01:28,760 --> 00:01:34,120 behavior and remember encapsulation, puts both the data and the behavior, 22 00:01:34,120 --> 00:01:39,310 into a single thing, a capsule, the class that you can then use. 23 00:01:42,970 --> 00:01:47,940 Understanding that we need to declare and initialize variables before we use them. 24 00:01:47,940 --> 00:01:51,110 We've been doing this all along, right, we declare variables, 25 00:01:51,110 --> 00:01:54,600 to reserve that space in memory and we provide a data 26 00:01:54,600 --> 00:01:59,000 type so that the compiler knows, how much space to set 27 00:01:59,000 --> 00:02:04,020 aside and what operations will be valid, on those particular variables. 28 00:02:04,020 --> 00:02:08,340 And we need to initialize them certainly, give them a value, before we use them, 29 00:02:08,340 --> 00:02:12,890 whether that means assign zero to a score that the player's going to 30 00:02:12,890 --> 00:02:18,450 have, or create a new object for a texture to defield, for example. 31 00:02:18,450 --> 00:02:21,260 But we need to somehow, initialize the value of 32 00:02:21,260 --> 00:02:23,860 that variable, before we actually try to use it. 33 00:02:27,660 --> 00:02:32,320 So here's a core idea behind the type system in C#. 34 00:02:32,320 --> 00:02:37,660 We have value types, that we talked about very early on, way back in Module 3. 35 00:02:37,660 --> 00:02:43,160 And those are the predefined types in general, don't include string, 36 00:02:43,160 --> 00:02:48,120 but the predefined types in general, that for 37 00:02:48,120 --> 00:02:52,890 the space and memory, that's reserved for that variable, it holds the value 38 00:02:52,890 --> 00:02:54,580 of that variable. 39 00:02:54,580 --> 00:02:57,990 As opposed to, reference types, that hold a 40 00:02:57,990 --> 00:03:02,040 reference to an object somewhere else in memory. 41 00:03:02,040 --> 00:03:06,810 Such that the value of a reference type variable, is 42 00:03:06,810 --> 00:03:10,590 not the actual object, it's a reference to the object. 43 00:03:10,590 --> 00:03:12,870 And if you want to think of that as the memory address of 44 00:03:12,870 --> 00:03:17,330 the object, that's fine because that's close enough, for this particular course. 45 00:03:21,780 --> 00:03:26,290 Another core idea behind object oriented, the object oriented 46 00:03:26,290 --> 00:03:30,650 paradigm, is the different between the class and the object. 47 00:03:30,650 --> 00:03:35,570 So as we know, because we've been using classes and objects since module four. 48 00:03:35,570 --> 00:03:41,750 As we know the class is the template, that expresses what data will be stored 49 00:03:41,750 --> 00:03:46,980 in a particular object, that is instantiated for that class and 50 00:03:46,980 --> 00:03:51,920 the behaviors are the methods that an object of that class, exposes. 51 00:03:51,920 --> 00:03:55,230 So the class is the template or the cookie cutter, 52 00:03:55,230 --> 00:03:59,620 and the objects are the things we produce, the cookies. 53 00:04:04,160 --> 00:04:09,770 So how to implement and call methods? Is again, you, I 54 00:04:09,770 --> 00:04:14,520 mean, our very first C# program, you were calling the console right line method. 55 00:04:14,520 --> 00:04:18,290 So calling methods, we understand that if it's an 56 00:04:18,290 --> 00:04:21,240 instance method, which is sort of what we use most 57 00:04:21,240 --> 00:04:25,250 commonly, we have the name of an object, variable, a 58 00:04:25,250 --> 00:04:29,170 reference type variable, dot and the method name, and then 59 00:04:29,170 --> 00:04:32,300 between parentheses we provide whatever arguments are required. 60 00:04:33,720 --> 00:04:37,720 For those less common but still used a lot 61 00:04:37,720 --> 00:04:39,950 methods, static methods, we put the console, sorry the console 62 00:04:39,950 --> 00:04:40,100 [LAUGH] 63 00:04:40,100 --> 00:04:40,600 we put the 64 00:04:43,110 --> 00:04:46,580 class name, followed by the dot, followed by the method 65 00:04:46,580 --> 00:04:51,590 name, followed by, between parenthesis, whatever arguments we need to provide. 66 00:04:51,590 --> 00:04:54,610 So that's calling the different kinds of methods 67 00:04:54,610 --> 00:04:57,620 and we also know, that methods can return 68 00:04:57,620 --> 00:05:01,210 either void, or something like a card, when 69 00:05:01,210 --> 00:05:02,810 we we're taking the top card from a deck. 70 00:05:04,280 --> 00:05:08,950 And so, in most cases, we're going to want to store 71 00:05:08,950 --> 00:05:13,280 that information that gets returned somehow, even if we 72 00:05:13,280 --> 00:05:17,760 directly pass it, as an argument to a new method. 73 00:05:17,760 --> 00:05:19,900 So for example in the blackjack game, where 74 00:05:19,900 --> 00:05:22,740 you would call the add card method on 75 00:05:22,740 --> 00:05:29,040 the blackjack hand object, and one of your arguments could be deck dot take top card. 76 00:05:29,040 --> 00:05:31,200 That means we weren't throwing away the card, that got 77 00:05:31,200 --> 00:05:34,570 returned from that method, we were just passing it along. 78 00:05:34,570 --> 00:05:37,240 And so when we call methods that return something 79 00:05:37,240 --> 00:05:40,100 other than void, we have a decision to make, 80 00:05:40,100 --> 00:05:42,100 about whether or not to store or use that 81 00:05:42,100 --> 00:05:45,030 information that gets returned, and usually the answer is yes. 82 00:05:46,050 --> 00:05:48,780 Implementing methods is something that we did in 83 00:05:48,780 --> 00:05:51,920 module 11, when we implemented the role method for 84 00:05:51,920 --> 00:05:54,080 the dice class, and when we implemented the 85 00:05:54,080 --> 00:05:57,120 draw and update methods for our rubber chicken class. 86 00:06:01,100 --> 00:06:07,080 So how do we use these predefined types that are available to us in C#? 87 00:06:07,080 --> 00:06:10,030 Well, we've been doing this for a long time, right? 88 00:06:10,030 --> 00:06:15,480 So these are the value types, I guess that's a little strong, right? 89 00:06:15,480 --> 00:06:18,100 So let's say, the predefined types in C# 90 00:06:18,100 --> 00:06:20,670 in the XNA framework, because you should also 91 00:06:20,670 --> 00:06:26,330 understand how to use a texture 2d, for example, or a rectangle, or a vector 2. 92 00:06:26,330 --> 00:06:30,282 So those are predefined, in terms of the framework in which we 93 00:06:30,282 --> 00:06:35,660 been working, even if they're not predefined by the C# programming language. 94 00:06:35,660 --> 00:06:37,150 So you should understand how you declare 95 00:06:37,150 --> 00:06:39,370 variables of these types, if they happen to 96 00:06:39,370 --> 00:06:43,500 have operations like rectangles do methods, you should 97 00:06:43,500 --> 00:06:45,589 be able to use those methods as well. 98 00:06:49,500 --> 00:06:51,150 We spent a little bit of time talking 99 00:06:51,150 --> 00:06:54,650 about string processing, and how we could use index 100 00:06:54,650 --> 00:06:57,880 of and substring, and we didn't actually use 101 00:06:57,880 --> 00:07:00,740 last index of, but that's commonly used as well. 102 00:07:00,740 --> 00:07:02,680 And you should make sure you remember, 103 00:07:02,680 --> 00:07:06,420 how you can use those string processing operations, 104 00:07:06,420 --> 00:07:09,440 to do interesting things, like extract the values 105 00:07:09,440 --> 00:07:12,390 from a comma separated value string, for example. 106 00:07:16,230 --> 00:07:21,150 We talked about selection, how our programs can make decisions, and how 107 00:07:21,150 --> 00:07:26,080 those decisions are either based on Boolean expressions, for if statements, or 108 00:07:26,080 --> 00:07:32,330 the value of a particular variable or an expression, for switch statements. 109 00:07:32,330 --> 00:07:37,460 And you should understand that, you should understand both that, those, statements 110 00:07:37,460 --> 00:07:41,180 are for making decisions and how you can actually use those statements, 111 00:07:41,180 --> 00:07:42,980 to make decisions. 112 00:07:42,980 --> 00:07:46,080 So remember, we have the sequence control structure, 113 00:07:46,080 --> 00:07:48,190 where we just do one thing after another. 114 00:07:48,190 --> 00:07:51,860 We have the selection control structure, where we can make decisions. 115 00:07:51,860 --> 00:07:57,260 And we have the iteration control structure, where we loop or iterate over 116 00:07:57,260 --> 00:08:02,363 the loop body, a certain number of times for four and for-each 117 00:08:02,363 --> 00:08:06,880 loops, or while some condition is true, for while loops. 118 00:08:09,940 --> 00:08:13,520 You should know how to do console input and output. 119 00:08:13,520 --> 00:08:19,170 Console output was console write line; console input was console read line. 120 00:08:19,170 --> 00:08:22,260 And remember, sometimes we will read in information from 121 00:08:22,260 --> 00:08:24,910 the user, that we need to convert to a different 122 00:08:24,910 --> 00:08:27,420 data type, and that's when we use things like, 123 00:08:27,420 --> 00:08:30,530 int dot parse or float dot parse, and so on. 124 00:08:34,210 --> 00:08:38,780 We talked about arrays, as a good way to store, a 125 00:08:38,780 --> 00:08:43,260 set of elements, that are all of the same data type. 126 00:08:43,260 --> 00:08:48,390 And so you should understand, how we declare arrays, how we use arrays, 127 00:08:48,390 --> 00:08:53,160 how we can use the index to access a particular element of an array. 128 00:08:53,160 --> 00:08:56,040 And, how we commonly use for loops and for 129 00:08:56,040 --> 00:08:59,590 each loops, to process in some way, each element 130 00:08:59,590 --> 00:09:00,170 of an array. 131 00:09:01,350 --> 00:09:05,570 Similarly, you should understand how collection classes 132 00:09:05,570 --> 00:09:07,110 work, and really, just the list class. 133 00:09:07,110 --> 00:09:10,202 I won't throw one of the other collection classes at you, 134 00:09:10,202 --> 00:09:14,000 on the final exam or anything, just the list class is fine. 135 00:09:14,000 --> 00:09:18,500 But understand, the key difference between arrays and lists, are that the lists can 136 00:09:18,500 --> 00:09:24,640 dynamically grow and shrink while arrays can't and other than that, 137 00:09:24,640 --> 00:09:26,970 they have very similar capabilities. 138 00:09:26,970 --> 00:09:32,220 We tend to use collection classes, most in our C# programs but 139 00:09:32,220 --> 00:09:36,910 because almost every modern programming language has arrays, we covered both of 140 00:09:40,830 --> 00:09:41,130 them. 141 00:09:41,130 --> 00:09:43,070 And even though I interspersed it throughout 142 00:09:43,070 --> 00:09:45,500 the course, we covered XNA as well. 143 00:09:45,500 --> 00:09:47,720 So you should understand the kinds of things 144 00:09:47,720 --> 00:09:51,400 we do in the XNA load content method, and 145 00:09:51,400 --> 00:09:54,320 how the update and draw methods relate to 146 00:09:54,320 --> 00:09:57,450 each other, in the context of the game loop. 147 00:09:57,450 --> 00:10:02,090 So we update and then draw, and update and then draw, and so on. 148 00:10:02,090 --> 00:10:04,150 And that you should only do appropriate things 149 00:10:04,150 --> 00:10:06,280 in the appropriate methods, you should never draw 150 00:10:06,280 --> 00:10:09,240 anything in the update method, you should never try to get the 151 00:10:09,240 --> 00:10:13,450 mouse state, while you're in the draw method, those kinds of things. 152 00:10:13,450 --> 00:10:19,480 We also added some functionality into the constructor, usually setting the window 153 00:10:19,480 --> 00:10:23,980 resolution for our game and occasionally, making the mouse visible as well. 154 00:10:27,550 --> 00:10:32,820 We also, early on, we just used draw rectangles to draw stuff, and 155 00:10:32,820 --> 00:10:37,380 then later, we started using source rectangles as well, so that we could use 156 00:10:37,380 --> 00:10:43,900 sprite strips to do things like, highlight or un-highlight a button or play 157 00:10:43,900 --> 00:10:46,520 an explosion animation, by moving the source 158 00:10:46,520 --> 00:10:49,970 rectangle across the sprite strip as appropriate. 159 00:10:49,970 --> 00:10:52,840 You should understand how to use both, draw 160 00:10:52,840 --> 00:10:56,180 and source rectangles, when you draw things in XNA. 161 00:10:59,920 --> 00:11:04,620 We also, at the very end of the course, we learn how we can also draw strings. 162 00:11:04,620 --> 00:11:06,660 So you should understand how we use a sprite 163 00:11:06,660 --> 00:11:09,820 font, to actually draw a string, and the fact that 164 00:11:09,820 --> 00:11:12,280 we call the draw string method, rather then the 165 00:11:12,280 --> 00:11:15,589 draw method, on a sprite batch object, to do it. 166 00:11:19,250 --> 00:11:23,460 And then we actually let the player interact with the game. 167 00:11:23,460 --> 00:11:25,950 So we learned how we could get mouse 168 00:11:25,950 --> 00:11:29,260 input, by capturing the current state of the 169 00:11:29,260 --> 00:11:33,230 mouse, calling the mouse, get state method, and 170 00:11:33,230 --> 00:11:34,390 then what we can do with the mouse. 171 00:11:34,390 --> 00:11:37,460 How we could process the buttons on the mouse or use the 172 00:11:37,460 --> 00:11:40,770 x and y to drag things around on the screen and so on. 173 00:11:41,920 --> 00:11:44,850 Even do things like highlight the quit button, 174 00:11:44,850 --> 00:11:48,120 when we were using the quit button too, because we could 175 00:11:48,120 --> 00:11:51,410 use the location of the mouse, to determine when it was over 176 00:11:51,410 --> 00:11:57,680 that button, for example, same thing with the required project, where 177 00:11:57,680 --> 00:12:01,180 you would highlight the number tiles when the mouse was over them. 178 00:12:01,180 --> 00:12:04,250 That was based on knowing, where the mouse was, 179 00:12:04,250 --> 00:12:08,170 relative to the draw rectangle for a particular number tile. 180 00:12:08,170 --> 00:12:10,070 So you should understand how we can do that 181 00:12:10,070 --> 00:12:11,220 input with a mouse. 182 00:12:14,170 --> 00:12:18,680 Similarly you should understand, how we did the gamepad input, it's okay if you 183 00:12:18,680 --> 00:12:23,690 don't have a 360 controller, I won't be asking any questions that would require 184 00:12:23,690 --> 00:12:28,700 you to have done sort of deep work with a 360 controller, but there's 185 00:12:28,700 --> 00:12:30,810 some general ideas about using a game 186 00:12:30,810 --> 00:12:34,100 pad particularly, versus a mouse that would apply. 187 00:12:34,100 --> 00:12:37,280 For example, we don't have, our gamepad is not 188 00:12:37,280 --> 00:12:39,180 a pointing device like the mouse, so we don't 189 00:12:39,180 --> 00:12:43,500 get an x and a y for anything related to the gamepad. 190 00:12:43,500 --> 00:12:45,960 So you should think about how we move things around with 191 00:12:45,960 --> 00:12:50,465 the gamepad, versus moving things around by making them follow the mouse. 192 00:12:50,465 --> 00:12:53,760 And of course, you know, there's lots of 193 00:12:53,760 --> 00:12:56,552 interesting things to do with gamepads as well, 194 00:12:56,552 --> 00:13:01,150 but like I said as long as you get the general ideas, you'll be in fine shape. 195 00:13:03,790 --> 00:13:08,540 And last but not least, we recently covered how use the keyboard. 196 00:13:08,540 --> 00:13:10,680 How you can get input from the keyboard, 197 00:13:10,680 --> 00:13:12,950 by getting the current state of the keyboard and 198 00:13:12,950 --> 00:13:16,250 some of the useful methods like Iskeydown, that 199 00:13:16,250 --> 00:13:21,170 we can use, to actually process that keyboard input. 200 00:13:21,170 --> 00:13:25,560 Now, this is an eight week course and we just blasted through 201 00:13:25,560 --> 00:13:29,560 all the big idea,s in a fairly short period of time here, 202 00:13:29,560 --> 00:13:34,150 but those are the core things that you should take out of the course. 203 00:13:34,150 --> 00:13:37,000 And you'll have access to the archived materials 204 00:13:37,000 --> 00:13:38,670 and everything for a long time to come. 205 00:13:38,670 --> 00:13:41,250 I'll talk about that in a different lecture, but 206 00:13:42,830 --> 00:13:46,660 you should understand those things that have been included. 207 00:13:46,660 --> 00:13:50,210 And if you do, if you've managed to say you 208 00:13:50,210 --> 00:13:55,656 know, dor e for most of your answers to these self-evaluation 209 00:13:55,656 --> 00:14:01,160 questions, then you probably will have no significant trouble with the final exam.