1 00:00:01,070 --> 00:00:01,400 OK. 2 00:00:01,430 --> 00:00:06,590 Welcome back to another lecture in this lecture, we are going to be talking about command line arguments, 3 00:00:06,590 --> 00:00:15,170 but we will also be kind of doing some more stuff with the input stream's input file stream not working 4 00:00:15,170 --> 00:00:20,240 with the output file stream in this lecture, but we will be practicing more with the input file stream. 5 00:00:20,240 --> 00:00:24,350 And we're also going to be, of course, introducing this new topic, Gramling. 6 00:00:25,880 --> 00:00:30,860 So we want to make our IO programs more flexible at this point. 7 00:00:30,860 --> 00:00:38,060 So currently, the only thing that we can really do with our input and output from files involves us 8 00:00:38,060 --> 00:00:41,210 hard coding the name of the file in our program, right? 9 00:00:41,210 --> 00:00:45,290 So we have that dot open and then we put like my file dot, right? 10 00:00:46,100 --> 00:00:47,210 So think about this. 11 00:00:47,210 --> 00:00:53,810 What if you compiled that program and you turn it into an executable and then you sent it to your friend 12 00:00:53,810 --> 00:00:55,250 and you're like losing this cool program? 13 00:00:55,250 --> 00:01:04,610 It reads, it reads a file, and then it like, does some stuff with that information and it prints 14 00:01:04,610 --> 00:01:05,480 some cool stuff out. 15 00:01:05,480 --> 00:01:08,120 And your friend is like, Oh, cool, let me run it. 16 00:01:08,510 --> 00:01:09,470 I'm going to make a file. 17 00:01:09,480 --> 00:01:15,140 And I call it like, super cool file data and I'm going to run the program. 18 00:01:15,150 --> 00:01:19,670 It's like, Well, your program is not going to be able to open that file because you told it to open 19 00:01:19,670 --> 00:01:20,870 my file that text. 20 00:01:22,110 --> 00:01:27,360 What if you just wanted to be able to send it to your friend and have them put whatever input file that 21 00:01:27,360 --> 00:01:28,020 they want? 22 00:01:28,050 --> 00:01:31,290 You know, once it's an executable, they can't really change your code. 23 00:01:31,290 --> 00:01:34,580 It's already turned into a binary file, right? 24 00:01:34,590 --> 00:01:35,160 So. 25 00:01:36,270 --> 00:01:39,960 It's kind of annoying you would basically he'd be like, Oh, it doesn't run. 26 00:01:40,620 --> 00:01:41,640 I need to. 27 00:01:41,760 --> 00:01:43,360 How do I get it to run with this simple file? 28 00:01:43,360 --> 00:01:49,170 And you're like, Oh, well, let me make another version that has, you know, it opens super cool 29 00:01:49,170 --> 00:01:50,910 filed or whatever. 30 00:01:50,910 --> 00:01:52,340 That would be kind of annoying. 31 00:01:52,350 --> 00:01:53,760 You'd have to go back and change your code. 32 00:01:54,090 --> 00:02:02,430 So how would we make this work without having to hard code the actual name inside the open function, 33 00:02:02,440 --> 00:02:03,330 the name of the file? 34 00:02:04,950 --> 00:02:09,580 So this is where these main function parameters and arguments come in. 35 00:02:09,600 --> 00:02:13,110 These are also referred to as command line arguments. 36 00:02:13,650 --> 00:02:17,130 You're probably seeing this and being like, Whoa, what is going on? 37 00:02:17,160 --> 00:02:19,410 The main function can have parameters. 38 00:02:19,530 --> 00:02:20,880 That's super weird. 39 00:02:21,690 --> 00:02:25,800 Where would the parameters come from if Maine is the first function to run? 40 00:02:25,830 --> 00:02:32,100 So isn't it like the operating system calling Maine and then all the rest of the program happens starting 41 00:02:32,100 --> 00:02:32,610 in Maine? 42 00:02:33,300 --> 00:02:35,580 So where are the arguments being sent from? 43 00:02:35,610 --> 00:02:43,260 Well, yes, it's kind of coming from the operating system, but really it can be coming from you and 44 00:02:43,260 --> 00:02:43,950 from you. 45 00:02:43,960 --> 00:02:50,340 I mean, by coming from the command line, the command prompt the console, whatever you want to call 46 00:02:50,340 --> 00:02:53,220 that bash whatever environment you're in. 47 00:02:54,810 --> 00:02:57,390 So let's go ahead and take a closer look at that. 48 00:02:57,810 --> 00:02:59,280 So what would that look like? 49 00:02:59,310 --> 00:03:00,600 Well, here I'm in bash. 50 00:03:01,830 --> 00:03:06,740 So what I would do if I had something like this is I would run my program. 51 00:03:06,750 --> 00:03:08,610 So we've obviously seen something like this. 52 00:03:08,610 --> 00:03:11,320 But then I put a space and I put something else. 53 00:03:11,790 --> 00:03:13,140 And what is this other thing? 54 00:03:13,770 --> 00:03:15,420 Well, it's my input file. 55 00:03:15,450 --> 00:03:22,350 I put an input file that text and what I am doing is I'm sending this all this information. 56 00:03:23,290 --> 00:03:28,810 To the main function right here, and this stuff right here is being used as parameters right here. 57 00:03:31,540 --> 00:03:38,260 So, OK, let's look into the parameters more what the these mean, we see an end ARG C and a cha pointer 58 00:03:38,380 --> 00:03:47,410 ARG V, which looks like an array, so ARG C stands for argument count and argument count is literally 59 00:03:47,410 --> 00:03:50,890 just one thing to thing like this. 60 00:03:50,890 --> 00:03:52,660 It's how many things we see here. 61 00:03:52,660 --> 00:03:54,820 There's a space separating two things. 62 00:03:55,510 --> 00:03:59,830 The first thing, though, happens to be our actual program that's getting rand. 63 00:03:59,830 --> 00:04:01,270 That's kind of weird, right? 64 00:04:01,720 --> 00:04:05,320 The second thing kind of makes sense because it's the input file we're interested in. 65 00:04:05,950 --> 00:04:07,120 But that's how it works. 66 00:04:07,330 --> 00:04:09,970 It takes both of those into consideration. 67 00:04:11,230 --> 00:04:19,810 The Cha star are the reasons for argument, Victor, we haven't introduced the concept of a vector yet, 68 00:04:20,230 --> 00:04:24,850 but right now you can just imagine a vector as another name for an array. 69 00:04:25,330 --> 00:04:29,290 So you can really think of this as argument array, and it looks like an array, right? 70 00:04:29,290 --> 00:04:30,520 Because it has these brackets here. 71 00:04:31,510 --> 00:04:32,470 So that's what it is. 72 00:04:32,830 --> 00:04:41,220 It's an array of what type of character you write, and it's a pointer so you can put Char Star Ruby 73 00:04:41,230 --> 00:04:43,930 in here or you can do char star star. 74 00:04:45,190 --> 00:04:47,370 So you can do two stars, one star. 75 00:04:47,380 --> 00:04:48,700 I'm just doing one right now. 76 00:04:49,600 --> 00:04:51,070 You can kind of look that up. 77 00:04:51,070 --> 00:04:55,360 If you'd like to know more about that convention and why you can have one and two stars, you know, 78 00:04:55,360 --> 00:05:00,610 a pointer that stores some pointers or just one tar star. 79 00:05:01,060 --> 00:05:03,670 So you can look that stuff up if you'd like to know more about that. 80 00:05:03,670 --> 00:05:10,450 But I'm just saying, you know, you can do either or I think it kind of depends on the compiler a little 81 00:05:10,450 --> 00:05:11,980 bit, but we're going to use our star. 82 00:05:14,380 --> 00:05:17,980 So RV is just an argument vector or an argument array. 83 00:05:18,670 --> 00:05:25,090 So let's break down this example a little bit more, so let's look at this bash line that I had right 84 00:05:25,090 --> 00:05:30,150 here where we're running my program, that CP and we are passing the main function. 85 00:05:30,430 --> 00:05:33,970 This information, which includes input file that, he added. 86 00:05:34,810 --> 00:05:36,880 In this example, artsy equals two. 87 00:05:36,910 --> 00:05:39,420 So this is one and this is two. 88 00:05:39,430 --> 00:05:41,020 So there's two things here. 89 00:05:41,050 --> 00:05:42,370 Total on this line. 90 00:05:43,420 --> 00:05:45,550 RV looks like this. 91 00:05:45,560 --> 00:05:48,670 It is an array, in fact, with all of this information. 92 00:05:48,880 --> 00:05:55,420 But you notice that we have my program, not CP, as the first element and input file that as the second 93 00:05:55,420 --> 00:05:57,490 element of the RV array. 94 00:05:58,570 --> 00:05:59,050 So. 95 00:06:00,830 --> 00:06:07,010 This my program does CP can be referred to as argue zero, right, we can index the array at position 96 00:06:07,020 --> 00:06:08,840 zero, which is the first thing. 97 00:06:09,650 --> 00:06:14,150 And so if we say argue zero, it should return to us this my program to CP. 98 00:06:14,570 --> 00:06:20,870 Similarly, we can do argue be one to get input file that because this is position one, right, we 99 00:06:20,870 --> 00:06:21,440 know that. 100 00:06:21,460 --> 00:06:26,360 We know that because we've done arrays already and we know about position starting at zero and then 101 00:06:26,360 --> 00:06:28,880 one and then two and then three and so on, right? 102 00:06:29,600 --> 00:06:35,300 So two things in here position zero, position one to get them out of the array, you would do arguing 103 00:06:35,300 --> 00:06:43,070 zero with the subscript operator to index it and argue, be one with the subscript operator and indexing 104 00:06:43,070 --> 00:06:43,610 it with one. 105 00:06:45,760 --> 00:06:51,610 So pretty strange that includes all this, including the program that you're actually running, right, 106 00:06:51,610 --> 00:06:54,130 which will be our whole program, but that's just the way it is. 107 00:06:55,660 --> 00:06:59,450 So now you kind of see how we can use this stuff. 108 00:06:59,470 --> 00:07:07,960 I'm going to increment or say, I'm going to show you one extra little thing before we go over a challenge. 109 00:07:09,610 --> 00:07:11,860 So this is looping with input. 110 00:07:11,860 --> 00:07:15,340 So I kind of mentioned this in the last lecture. 111 00:07:15,340 --> 00:07:23,590 I talked about us potentially going over looping with input files and the input file streams, and that 112 00:07:23,590 --> 00:07:24,910 is what I'm showing you right here. 113 00:07:25,240 --> 00:07:32,980 So you have made while loops and you have seen that we can repeatedly ask for input inside of the while 114 00:07:32,980 --> 00:07:33,430 loop, right? 115 00:07:33,430 --> 00:07:36,970 Like somewhere down here in the indentation within the brackets. 116 00:07:36,970 --> 00:07:38,230 But I don't have brackets here. 117 00:07:39,270 --> 00:07:44,910 You can also do something like this, so here we have an integer, we have an input file stream that 118 00:07:44,910 --> 00:07:45,570 we created. 119 00:07:45,780 --> 00:07:48,090 We open a file connected to the stream. 120 00:07:48,810 --> 00:07:50,040 But what's going on here? 121 00:07:50,070 --> 00:07:54,750 I'm basically putting this in a condition of the while loop. 122 00:07:54,750 --> 00:07:59,220 I'm using the stream and the input operator with a variable in here. 123 00:08:00,110 --> 00:08:10,310 This is basically saying loop, while you are able to get stuff from the stream out of the file as input 124 00:08:10,310 --> 00:08:13,910 and read it into my integer, so as long as this is possible. 125 00:08:15,310 --> 00:08:16,810 Then keep looping. 126 00:08:18,180 --> 00:08:24,840 And this is kind of a standard convention for reading from files, if you want to read files where you 127 00:08:24,840 --> 00:08:31,380 don't know how big they are, which is going to be a common thing, I mean, it's not normal to necessarily 128 00:08:31,380 --> 00:08:32,870 know how big the file is. 129 00:08:32,880 --> 00:08:38,190 You want to write a program that just kind of accepts whatever file size and just reads it. 130 00:08:39,540 --> 00:08:46,490 So this lets you loop through a file of some unknown length, and it will keep reading from the stream 131 00:08:46,560 --> 00:08:55,110 into this integer as long as that's possible until it reaches the end of the file, right when it reaches 132 00:08:55,110 --> 00:08:56,670 the end of the file. 133 00:08:57,690 --> 00:09:04,950 It'll kind of automatically stop because it won't be able to read into my integer anymore, and this 134 00:09:04,950 --> 00:09:07,260 is just a nice C++ convention. 135 00:09:08,350 --> 00:09:15,760 There's some interesting stuff going on with reading from files, there's actually like an end of file 136 00:09:16,120 --> 00:09:18,730 kind of Boolean flag that you can check. 137 00:09:19,270 --> 00:09:20,950 That's another useful thing. 138 00:09:21,460 --> 00:09:27,340 We might look at that a little bit more in the future, but for right now, I just want to introduce 139 00:09:27,340 --> 00:09:32,950 this concept so you can solve the next challenge that I'm about to show you on the next slide. 140 00:09:34,090 --> 00:09:38,980 So just remember that you can loop over a file with an input stream like this. 141 00:09:39,880 --> 00:09:47,050 I also want to show that it is possible to do something like this, except we haven't really done that 142 00:09:47,050 --> 00:09:47,380 yet. 143 00:09:48,520 --> 00:09:53,500 And of course, you know, this will just keep going as long as you're entering input. 144 00:09:53,500 --> 00:09:58,840 So you might want to add some sort of other condition here or something like that. 145 00:09:58,850 --> 00:10:04,060 But I do want to say that this is not something that is special just for a stream. 146 00:10:04,600 --> 00:10:10,760 You don't have to have some input file stream to be able to do something like this in a while loop. 147 00:10:10,780 --> 00:10:12,670 This is technically possible. 148 00:10:12,940 --> 00:10:18,820 Of course, you would want to think about when you're going to stop taking input from the console. 149 00:10:18,940 --> 00:10:19,300 Right? 150 00:10:19,990 --> 00:10:21,910 Just want to point that out? 151 00:10:21,910 --> 00:10:22,660 Put that out there. 152 00:10:22,990 --> 00:10:25,060 So let's go ahead and start with a challenge. 153 00:10:26,230 --> 00:10:28,420 So now that you know, how hard can we work? 154 00:10:28,420 --> 00:10:33,010 And if you already forgot, you can go back to the video and kind of look at what we've gone over. 155 00:10:34,270 --> 00:10:38,470 But what you should do is make a program that uses command line arguments. 156 00:10:38,860 --> 00:10:45,640 So you're going to use RC and RV stuff to read a file of integers into eight dynamic array. 157 00:10:45,640 --> 00:10:52,000 So you'll be using a new keyword, making a pointer, getting a dynamic array going and then the first 158 00:10:52,000 --> 00:10:53,980 line of the file that you read in from. 159 00:10:53,980 --> 00:10:57,100 That's going to be an integer that tells you how many numbers are in the file. 160 00:10:57,100 --> 00:10:59,680 So it also does not include that integer itself. 161 00:10:59,680 --> 00:11:00,010 So. 162 00:11:01,070 --> 00:11:05,780 For example, if we have if you make a file, which you should make for this problem, you should make 163 00:11:05,780 --> 00:11:07,520 your own text file with integers. 164 00:11:08,650 --> 00:11:12,370 At the top of that file, and if you have the integer 12. 165 00:11:13,470 --> 00:11:20,160 That means that below that, 12 in the file on the next lines, the subsequent lines, you're going 166 00:11:20,160 --> 00:11:28,230 to have 12 different lines where each line has a number that you will read into the array. 167 00:11:29,290 --> 00:11:37,480 And that 12 is not including the 12 itself, it's the counting starts on the next line below it. 168 00:11:37,750 --> 00:11:38,070 All right. 169 00:11:38,080 --> 00:11:40,870 So the first line says 12. 170 00:11:41,440 --> 00:11:47,620 The next line below it is where you start counting and that 12 tells you that there's going to be 12 171 00:11:47,770 --> 00:11:51,220 lines after that first line. 172 00:11:51,790 --> 00:11:52,240 OK. 173 00:11:53,350 --> 00:12:02,560 So once you have read in all of those lines into your array, then you should print out the contents 174 00:12:02,560 --> 00:12:03,550 of the array. 175 00:12:03,580 --> 00:12:08,920 Also remember, since it's a dynamic array, you should handle deleting that memory so it is now freed 176 00:12:08,920 --> 00:12:10,990 up at the end of your program. 177 00:12:11,410 --> 00:12:13,930 Also, remember to close the input file stream. 178 00:12:13,930 --> 00:12:17,860 So those are just two things that I want to remind you about. 179 00:12:18,610 --> 00:12:23,470 So you should make some file like input, text or whatever you want to name it. 180 00:12:24,990 --> 00:12:32,910 But that file should contain at least 10 numbers in it, not including the first line that tells you 181 00:12:33,390 --> 00:12:40,440 how many numbers are in the file and also make sure that you're not hard coding this file name. 182 00:12:40,440 --> 00:12:46,380 You should be getting it from the command line arguments like we just discussed and accessing it with 183 00:12:46,380 --> 00:12:47,580 the the right. 184 00:12:48,840 --> 00:12:56,250 The argument vector, so I'm going to go ahead and let you get into this, if you're still a little 185 00:12:56,250 --> 00:13:03,060 confused on how to make a text file, you can basically make a new file in vs code and you can just, 186 00:13:03,060 --> 00:13:08,340 of course, make one and then just make a dot extension file and open that. 187 00:13:08,340 --> 00:13:08,880 And then. 188 00:13:10,260 --> 00:13:19,170 Same thing, you can save it as text with this code if you are on Sea Lion, which don't worry, we 189 00:13:19,170 --> 00:13:22,080 will be transitioning to Sea Lion very soon. 190 00:13:22,470 --> 00:13:27,990 I will be using Sea Lion, I'll be using all sorts of editors and mixing and matching, you know, but 191 00:13:27,990 --> 00:13:33,720 I'm going to be using Sea Lion pretty soon here exclusively because we're going to be making bigger 192 00:13:33,720 --> 00:13:34,260 programs. 193 00:13:34,890 --> 00:13:37,860 I will show you how to make a. 194 00:13:39,780 --> 00:13:44,880 Set up in sea line for this problem, like use the command line arguments because it's a little it's 195 00:13:44,880 --> 00:13:46,050 not as straightforward. 196 00:13:46,270 --> 00:13:50,160 It would be good for you to be able to google that stuff on your own and figure it out. 197 00:13:51,000 --> 00:13:54,600 You just need to edit the configurations, but I will go ahead and show you that. 198 00:13:56,000 --> 00:14:01,730 So first, I will go ahead and show how to do that sea lion and then I will go over the solution to 199 00:14:01,730 --> 00:14:07,910 this small challenge, but make sure to attempt it yourself before looking at the solution. 200 00:14:07,910 --> 00:14:11,370 As always, do not try and look up answers to this. 201 00:14:11,390 --> 00:14:16,760 You can look up syntax stuff if you are forgetting some syntax, but make sure to solve the problem 202 00:14:16,760 --> 00:14:17,270 on your own. 203 00:14:18,140 --> 00:14:21,950 If you cannot solve it on your own, then you don't have to worry. 204 00:14:21,950 --> 00:14:24,980 You can wait to the solution, but please try your hardest to solve it on your own. 205 00:14:26,150 --> 00:14:28,700 So let me go ahead and open sea lion first. 206 00:14:32,090 --> 00:14:33,590 I want to go ahead and. 207 00:14:34,730 --> 00:14:40,140 Make a new project from sources, I kind of just have this directory here. 208 00:14:41,960 --> 00:14:51,830 Right here we have the files that are all just kind of smashed into the first program folder. 209 00:14:51,890 --> 00:14:54,800 So remember, I'm just kind of storing it messily here. 210 00:14:55,370 --> 00:14:57,560 You should definitely organize it better than I am. 211 00:14:57,560 --> 00:14:59,690 You should not smash it all into this folder. 212 00:14:59,700 --> 00:15:03,800 I think I've already mentioned that, but you should have your own folders and organize all of these. 213 00:15:05,050 --> 00:15:09,430 Programs that we've been going over so far, so I have this seemed arcs right here. 214 00:15:09,730 --> 00:15:14,380 It has this zip file, this kind of blinking here, and I'm going to solve it in VSCO. 215 00:15:14,380 --> 00:15:22,150 But first, I'm going to show you how to set it up with Sea Lion, so I'm going to go ahead and use 216 00:15:22,150 --> 00:15:22,480 this. 217 00:15:22,930 --> 00:15:29,140 So this right here, I just press, OK, I make a new sea make project. 218 00:15:29,140 --> 00:15:32,440 It's just going to have these project files here. 219 00:15:33,430 --> 00:15:34,750 So I'm going to say, OK. 220 00:15:38,740 --> 00:15:39,730 This should be. 221 00:15:41,660 --> 00:15:42,030 Yeah. 222 00:15:48,290 --> 00:15:48,980 I won't do that. 223 00:15:51,040 --> 00:15:51,430 All right. 224 00:15:51,580 --> 00:15:55,510 So now what we're going to do, so we have this file right here, right? 225 00:15:58,970 --> 00:16:01,670 So let me increase this size a little bit. 226 00:16:06,180 --> 00:16:10,650 So you can see what's going on here, but this is just some basic file. 227 00:16:10,670 --> 00:16:12,530 It has some command line argument here. 228 00:16:12,530 --> 00:16:16,850 I've already put that here and then I don't have anything else in it and I will solve the problem in 229 00:16:16,850 --> 00:16:18,170 a moment I'm going to do in vs code. 230 00:16:18,860 --> 00:16:27,140 But what you need to do to be able to pass some files as input to your program, since you may not be 231 00:16:27,140 --> 00:16:30,530 using a command line down here like in the terminal. 232 00:16:30,740 --> 00:16:33,170 So here's there's like a terminal down here, right? 233 00:16:34,010 --> 00:16:36,260 So I'm assuming in here. 234 00:16:37,740 --> 00:16:47,940 We have this terminal down here, but maybe you're not necessarily going to be running this program 235 00:16:47,940 --> 00:16:56,460 down here like the CMG are, it's sleepy and then put input file that takes you like that. 236 00:16:56,970 --> 00:16:58,170 You can do that in the terminal. 237 00:16:58,180 --> 00:17:02,460 But what I want to show you is if you want to just run it directly from sea lion. 238 00:17:04,320 --> 00:17:08,550 You can actually go up here and go to edit configurations. 239 00:17:09,880 --> 00:17:17,620 And here in program arguments, you would put your input once input, okay, so let's say you have a 240 00:17:17,620 --> 00:17:21,700 file in here in your directory, so I'm going to say cancel right now. 241 00:17:22,060 --> 00:17:23,590 Let's see you want to make a new file. 242 00:17:23,590 --> 00:17:28,900 So I right click here, I say new and I just say file and I say input. 243 00:17:30,070 --> 00:17:31,160 Now I have some input. 244 00:17:32,350 --> 00:17:39,460 I say, like, you know, I'm going to put 12 things here, and then I just put like, you know, a 245 00:17:39,460 --> 00:17:45,010 bunch of random things until there's like. 246 00:17:46,230 --> 00:17:51,690 Well, you know, there should be 12 here, one two three four five six seven eight nine, 10, 12, 247 00:17:51,690 --> 00:17:52,030 13. 248 00:17:52,050 --> 00:17:53,130 OK, so I guess there's. 249 00:17:57,110 --> 00:17:57,430 13. 250 00:17:58,010 --> 00:18:05,270 Yeah, so there should be, you know, 12 things in here, you make some file like this. 251 00:18:05,270 --> 00:18:10,310 Maybe, you know, I go ahead and I just save everything and then I go back here and I'm like, Well, 252 00:18:10,310 --> 00:18:11,100 how do I use this? 253 00:18:11,100 --> 00:18:13,700 As if I didn't want to use the terminal so I can go here. 254 00:18:13,700 --> 00:18:15,390 Any configurations go here. 255 00:18:15,870 --> 00:18:17,010 Input text. 256 00:18:17,600 --> 00:18:19,560 It's going to be program arguments. 257 00:18:19,580 --> 00:18:21,920 You can think of this as arguments to main. 258 00:18:22,310 --> 00:18:28,130 So it's going to send this whatever you type in here as the arguments for main, just like you would 259 00:18:28,130 --> 00:18:30,470 do in the terminal down there, like we've discussed. 260 00:18:30,920 --> 00:18:37,070 You also might want to go here and click on this and find your actual theme the ARGS Directory, your 261 00:18:37,070 --> 00:18:42,170 project directory and then click Apply and OK. 262 00:18:42,920 --> 00:18:50,510 And after that, you will be able to run it normally here, and you would be able to see your input 263 00:18:50,630 --> 00:18:55,250 text file would actually get used here in the arguments to me. 264 00:18:56,300 --> 00:18:58,340 OK, so I just wanted to point that out. 265 00:18:58,340 --> 00:19:00,830 So you're able to use that. 266 00:19:01,790 --> 00:19:03,240 So I'm actually going to exit out of here. 267 00:19:03,260 --> 00:19:04,310 I'm not going to save that. 268 00:19:05,450 --> 00:19:14,200 So let's go ahead and head over to vs code so we can so we can deal with that. 269 00:19:14,210 --> 00:19:17,540 So I'm actually going to open the code here. 270 00:19:21,890 --> 00:19:25,280 So I've got this seemed ARG's copy here. 271 00:19:25,580 --> 00:19:34,630 I'm going to go ahead and navigate to this directory, so I'm going to say first program and CMT Arts. 272 00:19:35,450 --> 00:19:36,920 So now I am here. 273 00:19:39,150 --> 00:19:41,070 Let's make sure that we can actually. 274 00:19:43,440 --> 00:19:44,910 See stuff big enough. 275 00:19:49,170 --> 00:19:54,960 OK, so let's go ahead and get started with these solutions, so what do we have to do here? 276 00:19:55,170 --> 00:19:58,410 So we're going to need to go ahead and go back to our problem statement. 277 00:19:59,570 --> 00:20:05,300 So we want to make a program that uses a command line arguments to read a file of integers into a dynamic 278 00:20:05,300 --> 00:20:05,600 array. 279 00:20:05,630 --> 00:20:07,460 Let's just get started with that knowledge right here. 280 00:20:07,470 --> 00:20:14,660 So something that I'm going to do is I'm going to make sure that the user is in fact entering into arguments 281 00:20:14,660 --> 00:20:17,610 that our count should be to write Argosy should be to. 282 00:20:17,630 --> 00:20:27,530 So I'm going to say if our fee is not equal to two, I want to print some message. 283 00:20:28,730 --> 00:20:34,160 Some of this you control and see, I want to say usage to show how they use it. 284 00:20:34,160 --> 00:20:44,030 And I'm going to say, like, you know, programs, something like this program name. 285 00:20:44,030 --> 00:20:51,230 And then let's just say input file names, something like that. 286 00:20:53,040 --> 00:20:55,290 So that should be the way that you should use it. 287 00:20:59,860 --> 00:21:03,940 So this is where the input file names should go, and then if they if they fail to do that correctly, 288 00:21:03,940 --> 00:21:10,990 I'm honestly just going to exit immediately with this negative one exit code because that is something 289 00:21:10,990 --> 00:21:11,230 bad. 290 00:21:11,230 --> 00:21:16,420 They should not have tried to run it without an input file name because it would cause problems. 291 00:21:17,620 --> 00:21:19,330 So I'm going to go ahead and do that. 292 00:21:19,330 --> 00:21:25,030 And then down here, if it if that is all good to go, I'm going to go ahead and create an input file 293 00:21:25,030 --> 00:21:25,420 stream. 294 00:21:25,420 --> 00:21:30,310 So I'll just say extreme and call this my stream. 295 00:21:31,210 --> 00:21:33,070 So now we have an input file stream. 296 00:21:33,700 --> 00:21:37,570 What I'm then going to do is I'm going to see. 297 00:21:37,570 --> 00:21:45,370 I also have an integer here, so I'm going to say and I will say in size because I'm going to want to 298 00:21:45,370 --> 00:21:47,060 read in that size right. 299 00:21:47,080 --> 00:21:52,960 The first line should be the size of all the stuff in the file, but it's also going to be the size 300 00:21:52,960 --> 00:21:54,220 for our dynamic array. 301 00:21:55,120 --> 00:22:00,700 After that, I'm going to have the value, which is basically each one of the numbers that we're going 302 00:22:00,700 --> 00:22:01,480 to read in. 303 00:22:02,020 --> 00:22:08,080 And after that, I'm going to have another and that is just going to be position or count or something 304 00:22:08,080 --> 00:22:08,590 like that. 305 00:22:08,740 --> 00:22:10,090 You call it position count. 306 00:22:11,440 --> 00:22:15,580 And that's actually going to start at zero because I'm going to use a while loop and I'm going to want 307 00:22:15,580 --> 00:22:23,260 to increment the position so I can use that to index the array right because we want some sort of position 308 00:22:23,260 --> 00:22:28,900 that we can use while we're looping, just like you've done before, to put stuff in the ordered positions 309 00:22:28,900 --> 00:22:29,560 in the array. 310 00:22:31,380 --> 00:22:34,260 I also should probably go ahead and just declare my array. 311 00:22:35,910 --> 00:22:40,740 But I think what I'm going to do is I need to read in from the stream first to get that size right. 312 00:22:41,460 --> 00:22:50,940 So what I will do is I will say my stream, my stream that open. 313 00:22:51,720 --> 00:22:53,000 What am I going to put here now? 314 00:22:53,010 --> 00:22:55,530 Am I going to put input, text or something? 315 00:22:55,530 --> 00:22:57,200 No, I'm not going to. 316 00:22:57,420 --> 00:23:03,840 I have this file right here numbs that text that has 12 numbers. 317 00:23:06,810 --> 00:23:10,830 So I think one, two, three four five, six, seven eight. 318 00:23:13,040 --> 00:23:17,270 Nine, 10, 11, 12, 13 numbers, so let me tell you, I made the same mistake as last time. 319 00:23:17,550 --> 00:23:24,290 So go ahead and save that and I'm not going to put non-stop text in here because that would be hard 320 00:23:24,290 --> 00:23:25,570 coded and that defeats the purpose. 321 00:23:25,580 --> 00:23:26,630 That's not what we're doing. 322 00:23:27,560 --> 00:23:28,850 What am I going to put in here? 323 00:23:28,970 --> 00:23:35,150 Well, I'm going to use our movie because we're going to pass on his command line arguments and what 324 00:23:35,150 --> 00:23:39,890 position was it in if we have program name as the zero position? 325 00:23:40,520 --> 00:23:42,800 This is going to be the first position. 326 00:23:42,800 --> 00:23:43,820 We have two things. 327 00:23:43,820 --> 00:23:47,570 The first thing, the second thing, but this is position zero, this position one. 328 00:23:48,830 --> 00:23:56,420 So I'm interested in R V and the argument vector or the argument a position one that's going to give 329 00:23:56,420 --> 00:24:01,340 me the name of the input file right here is going to take that and put it right here. 330 00:24:01,340 --> 00:24:07,030 And it's going to be a string, just like as if we put, you know, NUM's Dot. 331 00:24:10,730 --> 00:24:12,830 So let's go ahead and do that. 332 00:24:12,830 --> 00:24:15,440 And once we open that, what is the first thing we want to do? 333 00:24:15,470 --> 00:24:25,250 Well, we want to read in that no reading from the input stream right into this size because we know 334 00:24:25,250 --> 00:24:26,750 that that's going to be the first thing. 335 00:24:27,050 --> 00:24:37,400 And once we have that size, then what we can do is say something like this and let's just say and poyner, 336 00:24:37,400 --> 00:24:46,640 my array equals new and and we're going to save this dynamic array is going to be size. 337 00:24:48,070 --> 00:24:51,220 It's going to have the size sighs we've read into the size already, OK? 338 00:24:52,420 --> 00:24:54,310 So what do we do now? 339 00:24:54,370 --> 00:25:00,310 Well, now we want to go through the rest of the items in the array and save them, so the rest of the 340 00:25:00,310 --> 00:25:02,270 items in the file and save them into the array. 341 00:25:02,290 --> 00:25:07,420 So it says, read a file of integers into a dynamic array. 342 00:25:07,420 --> 00:25:09,220 We've handled this first line. 343 00:25:09,220 --> 00:25:10,180 That's an integer. 344 00:25:10,450 --> 00:25:12,640 It states how many numbers are in the file we've already put. 345 00:25:12,640 --> 00:25:14,160 That is the size of the array. 346 00:25:15,300 --> 00:25:19,200 So we want to read it into the array and then print it out, so let's go ahead and do that. 347 00:25:20,110 --> 00:25:29,370 I must say while we are able to have my extreme excuse me read into and what are we going to read into 348 00:25:29,370 --> 00:25:32,010 what variable unmarried into value? 349 00:25:32,010 --> 00:25:37,200 Because that's going to hold each number that we're reading from the file. 350 00:25:37,890 --> 00:25:42,450 So what it'll be like is, you know, first time the loop goes around, it'll be for next time, it 351 00:25:42,450 --> 00:25:43,000 will be eight. 352 00:25:43,020 --> 00:25:44,880 Next time be thirty four and so on. 353 00:25:45,750 --> 00:25:52,650 Some might say while we can go, most read from my stream and store that data into the value variable. 354 00:25:55,520 --> 00:26:02,320 Then what I'm going to do down here is I'm going to say position count is already holding the value 355 00:26:02,330 --> 00:26:02,870 zero. 356 00:26:02,870 --> 00:26:04,180 I started at zero, right? 357 00:26:04,190 --> 00:26:12,940 So I'm going to use my ram, the same my array and I'm going to say position, position, count, right? 358 00:26:12,950 --> 00:26:14,690 So we're going to index it a position count. 359 00:26:14,690 --> 00:26:15,760 It starts at zero. 360 00:26:15,770 --> 00:26:23,330 So the first time we go through the loop, it's going to store position zero right of the array and 361 00:26:23,330 --> 00:26:25,370 we're we've already read in the size. 362 00:26:26,620 --> 00:26:27,700 Which is 12. 363 00:26:27,760 --> 00:26:30,880 So the next number we're going to read in is going to be four. 364 00:26:31,000 --> 00:26:31,360 Right? 365 00:26:32,670 --> 00:26:37,380 So I'm going to say that I'm going to store value each time, right? 366 00:26:38,070 --> 00:26:41,460 And if I want to store value each time and have it be for. 367 00:26:42,600 --> 00:26:46,380 And then the next thing in there is eight, and the next thing is 34, I need to change the position, 368 00:26:46,440 --> 00:26:54,630 I need to increment it, so I'm actually going to do a position count plus plus and that'll change my 369 00:26:54,630 --> 00:26:55,140 position. 370 00:26:56,720 --> 00:27:01,520 So this is enough to successfully read into every position in the array. 371 00:27:02,390 --> 00:27:05,180 So we've already got the size of the file. 372 00:27:05,900 --> 00:27:11,630 That's assuming, of course, that this is correct and there actually are 12 things in the file. 373 00:27:12,920 --> 00:27:17,780 So I'm actually going to remove this line right here as well and save that just because I don't need 374 00:27:17,780 --> 00:27:18,260 that line. 375 00:27:20,440 --> 00:27:27,280 So let's go ahead and deal with that now we can print out all the stuff in the array, right? 376 00:27:27,460 --> 00:27:29,200 So I'm going to use a for loop for this. 377 00:27:30,100 --> 00:27:33,640 So at this point, I can close my stream because I don't need to read anything anymore. 378 00:27:33,640 --> 00:27:41,080 So I'm going to say my stream got close, then I'm going to do four and I equals zero. 379 00:27:41,530 --> 00:27:48,160 I is less than size I plus plus because we're going to loop as long as there are things in the array 380 00:27:48,160 --> 00:27:51,010 and the array has size number of things, right? 381 00:27:52,030 --> 00:27:59,030 And then now what I'm going to do is, say, a steady out and I'm going to put my array. 382 00:28:00,470 --> 00:28:04,720 I and then I'm just going to put a little space in between. 383 00:28:06,490 --> 00:28:12,250 Then down here, before we return zero, we should delete the array, right, so I'm going to say delete 384 00:28:12,430 --> 00:28:17,230 because we dynamically allocated it, so we're going to put these brackets, so delete everything in 385 00:28:17,230 --> 00:28:21,430 the array and I'm going to save my arrays so it'll delete that whole contiguous chunk of memory. 386 00:28:21,730 --> 00:28:23,740 We've talked about this syntax before, right? 387 00:28:24,460 --> 00:28:29,950 So now we are successfully freeing up that memory of our dynamically allocated array since we use the 388 00:28:29,950 --> 00:28:30,670 keyword new. 389 00:28:31,030 --> 00:28:34,660 We've closed our stream, we're reading and everything OK. 390 00:28:35,110 --> 00:28:40,150 And it seems like we have something to catch if the user does not enter the correct number of arguments. 391 00:28:41,050 --> 00:28:42,400 So we should be good to go. 392 00:28:42,430 --> 00:28:44,350 I'm going to go ahead and save this. 393 00:28:46,290 --> 00:28:52,110 And then I am going to go ahead and compile it, source CGI plus plus you just can't make sure that 394 00:28:52,110 --> 00:28:52,940 it's actually here. 395 00:28:52,950 --> 00:29:01,560 So if I say cat, the args that CP, so I'm in here. 396 00:29:04,090 --> 00:29:06,220 Let's see if we have. 397 00:29:07,850 --> 00:29:12,020 So we all have this CMake stuff that got put in here as well. 398 00:29:15,190 --> 00:29:20,230 So this is actually stored in first program, so I should move that I'm actually going to. 399 00:29:23,970 --> 00:29:26,830 This was in our CMake program, so I'm actually in the wrong direction. 400 00:29:26,850 --> 00:29:33,900 I'm going to go back one directory because our thing that's actually here, if we can't see in the hour 401 00:29:33,900 --> 00:29:35,460 is one copy. 402 00:29:36,420 --> 00:29:38,250 It has all this stuff in it. 403 00:29:38,730 --> 00:29:41,880 It's not the, you know, this shows all of our code. 404 00:29:42,870 --> 00:29:44,220 This is what we're dealing with right now. 405 00:29:44,230 --> 00:29:48,360 We're not dealing with the one that I had in the CIMIC. 406 00:29:48,780 --> 00:29:49,500 Sorry, the. 407 00:29:50,730 --> 00:29:52,380 Sea lion directory that we had. 408 00:29:53,460 --> 00:30:02,280 So let's go ahead and compile this, let's say, seemed parks one that CBP dash Oh, and I'm just going 409 00:30:02,280 --> 00:30:06,690 to say CMT Arts Dot XY. 410 00:30:08,410 --> 00:30:11,830 So that compiles, OK, let's go ahead and run it and see if it works, OK? 411 00:30:12,280 --> 00:30:15,750 So let's do you know CMA, CMT Arts? 412 00:30:16,300 --> 00:30:16,480 Yes. 413 00:30:17,650 --> 00:30:18,880 And let's check it out. 414 00:30:20,030 --> 00:30:21,750 Oh, well, look at that. 415 00:30:21,770 --> 00:30:27,710 I tried to run it and it didn't work, it said that I need to do usage program name, input, file name. 416 00:30:29,510 --> 00:30:34,340 So you notice how that worked at exited right away, and it printed out this message now that informs 417 00:30:34,340 --> 00:30:40,220 me, Oh, I can't just run it like this, I need to run it with, of course, you know, I've used this 418 00:30:40,220 --> 00:30:41,420 bash syntax here. 419 00:30:41,420 --> 00:30:45,800 You would use whatever you need to use for whatever shell or console you're in. 420 00:30:47,690 --> 00:30:51,590 But I need to use an input file name, so let's go ahead and do this again, and let's use the NUM's 421 00:30:51,590 --> 00:30:52,130 Dot. 422 00:30:53,060 --> 00:30:53,850 Now I'm to. 423 00:30:56,760 --> 00:30:57,840 And look at that. 424 00:30:57,870 --> 00:30:59,400 Let's take a look at these numbers here. 425 00:30:59,410 --> 00:31:01,010 We have four, eight four. 426 00:31:01,890 --> 00:31:03,340 Let's just match it up with this. 427 00:31:03,340 --> 00:31:09,000 So four eight three four one 13 five 26. 428 00:31:10,520 --> 00:31:11,750 Four to seven. 429 00:31:13,120 --> 00:31:18,760 54, one, 20, seven, nine, two thousand seven hundred forty nine, so it printed out and read all 430 00:31:18,760 --> 00:31:22,450 those in and successfully printed them all out in a line. 431 00:31:24,130 --> 00:31:30,190 So if you weren't able to get that like I always say, don't worry, you know, we keep introducing 432 00:31:30,190 --> 00:31:34,750 is pretty new, pretty difficult projects, sorry concepts. 433 00:31:35,290 --> 00:31:41,020 And you know, I don't expect you to immediately just understand everything right off the bat. 434 00:31:41,470 --> 00:31:45,570 So if you don't understand it, go ahead and walk back through it. 435 00:31:45,580 --> 00:31:46,690 Look through all the code. 436 00:31:47,470 --> 00:31:55,300 You know, the stuff that we did here was just to kind of make sure that the user knows how to use the 437 00:31:55,300 --> 00:31:57,760 program correctly with an input file name. 438 00:32:00,030 --> 00:32:05,160 Right here, we declare all of our variables, you know, this is for the size of the array that we're 439 00:32:05,160 --> 00:32:11,160 going to dynamically allocate, which is the 12 appears the first line. 440 00:32:11,250 --> 00:32:14,100 This is to hold each one of the values. 441 00:32:14,100 --> 00:32:19,380 We're going to keep changing what it holds, which will be first four, then eight point thirty four 442 00:32:19,380 --> 00:32:20,840 each time our loop goes right. 443 00:32:20,850 --> 00:32:26,760 So we did that value position count is just so we can index our array at the correct position. 444 00:32:26,760 --> 00:32:31,950 And since we're looping, we do a plus plus to bring it from zero to one to two to three. 445 00:32:31,950 --> 00:32:40,500 And then we store four at position zero, a position one, three, four, position two and so on by 446 00:32:40,500 --> 00:32:41,550 doing this right here. 447 00:32:43,330 --> 00:32:49,210 We've opened the stream, we read the initial size in before we started, then reading into the values 448 00:32:49,210 --> 00:32:49,960 from the stream. 449 00:32:50,050 --> 00:32:55,450 From that file, we closed the stream before we printed it out and then we made sure to delete our dam 450 00:32:55,640 --> 00:32:56,600 dynamically allocated. 451 00:32:58,300 --> 00:32:58,810 OK. 452 00:32:58,840 --> 00:33:02,120 So with that, I will see you in the next lecture. 453 00:33:02,150 --> 00:33:09,120 We are going to go over something that is a little bit easier to use now than an array. 454 00:33:09,130 --> 00:33:13,900 It's going to introduce a really cool new concept, and we're going to actually talk about that vector 455 00:33:14,680 --> 00:33:17,640 that I was mentioning when I said our argument vector. 456 00:33:17,650 --> 00:33:24,190 We're going to talk about a new data type, which is actually going to be a new container called a vector. 457 00:33:24,190 --> 00:33:28,360 And it's like an array, but it's much fancier and easier for you to use. 458 00:33:29,080 --> 00:33:30,820 So with that, I see you in the next lecture.