over the years, I've learned an awful lot of programming languages. But the one thing that I can't be bothered to do is to read my way through one of those enormous books, you know, page 1 to 800, telling you everything about this programming language. And yet, I've learned Ruby, C, Java, Object Pascal, Modular 2, lots and lots of programming languages. I've been programming since the 1980s, and I've had plenty of time to figure out a way of learning a language as effectively as possible. And that's what this video is about. What I don't do is I don't read huge manuals from page one to page 800. I don't do hundreds and hundreds of little programming exercises. I know that some programmers, when I've taught courses on programming, get very wound up, very obsessed with solving problems, of having exercises to do. Exercises have their place, and they can be useful for some things, but that's not my approach to learning a new language, to learn a new language quickly.

and effectively pick a project. Get programming. Simple as that. I'll show you what I mean. As always, if you followed some of my other tutorials, you'll probably guess the project I'm going to pick. It's going to be a simple Adventure game. Adventure games are great because they bring in all sorts of stuff: string handling, class libraries, file handling, just about everything, really. But for you, if you don't like adventure games, pick something else. It could be a disutility. It could be, I don't know, I really have no idea what interests you, but find something that you're interested in and start to learn. That way, I'll show you how I do this. I'm going to show you how I started learning the D language. I picked D because it's quite a fairly well-established language, but probably one that most people are not familiar with. I've never really programmed D before. I've been aware of it over the years, but I've had to learn from scratch. So I'm going to show you how I got from no

knowledge of D to writing a simple Adventure game in about 3 hours. Let's see how I got started. Clearly, the first thing you have to do when learning a new language is install the compiler or interpreter. That is the thing that's going to run the language for you. For D, I've gone to the programming website and found the download page. There are lots of downloads here for Windows and various versions of Linux and MacOS. If I'm programming Windows, I've decided that I'm going to use Visual Studio, and there is a Visual Studio plugin called Visual D. I can download that. It includes the D compiler so I don't have to do more than one step. But if you're using other operating systems, then Visual Studio Code is quite well supported. It takes a bit more setup and unless you're very familiar with it, it'll take a bit of learning, which is why I'm really more comfortable with Visual Studio. Then I need some reference material. Well, the D site has this documentation, fairly comprehensive documentation to the language and its

libraries. And just as an added extra, there are also extra resources you can see here. There are various tools, editors, tutorials, and books. So I'm going to use this book, this online book. Or you can also get a PDF version so that I can dip in when I need some extra help. So having got my IDE up and running, this is the one that's in Visual Studio. The next thing to do is to start writing something. So start a project. I can search in Visual Studio for a particular language. If you're using another IDE or text editor, of course, this step is going to be different. Just select an application and see what happens. D application. I'll just use all the defaults. Now it's prompting me console. Yeah, I'll go for console. This is the standard reference D compiler. Okay, I'll accept that. Finish. Let's see what happens. So it's gone away and it's generated something. I can see there's a D program file here. Let's have a look what's in it. Ah, so it's created a simple file for me.

let me try running that and see if it works. So it's compiling it and ah pop down again. So I need to put a break point. Break point will stop it exiting, I hope. And let me look at okay. So hello D world, that looks okay. What do I do next? Let's stop this back in here. Well, let's see if I can guess my way through it. I've got some experience with C and C-like languages. Let's try an array of chars, a string in other words. Turns out that D has more than one way of doing strings, but I'm going to stick with this Char array. Call it s. So this is me guessing my way through the language so far. It works okay. So let's have a look. I've got wrin. Well, let's see if there's a reedin. Reedin is the same name. I happen to know these from Pascal. These are standard names in Pascal. See if see if this works inde D. And it's looking good so far. It's got no no. The error squiggly is gone so.

let's see if I can append that to this string. Uh, normally that's with a plus s. Ah, it's not liking that. So that's where I've had to resort. This is the first time when I was learning this that I had to resort to the documentation, and it tells me that. I'll save you the time. I won't show you it all now, but you just look it up in online documentation, and it says tilder is the way of appending one string to another. And instead of putting a break point this time, I'm going to put redin, and just like Pascal, it also lets me omit the uh empty brackets if I wish to. And I just found that again by trial and error. Uh, you know, no special magic on this. So let's see what happens. Okay, so enter my name. It should read that, assign it to the string s, and it displays the string. It's paused at the end because of that final reading I put. It's waiting to read the final line. It'll do that when I press enter.

there you go. So, that's my first program. All of that was done with guesswork, apart from this one thing. I had to look at this tilder to find out how to append a string. So, that was my first 5 minutes. I said that. I took about 3 hours. Let's see what I accomplished in the first hour. Well, I'm trying here to create a class. That's a class that's going to define an object. When I've looked at other D tutorials, they leave classes and object orientation on the whole really till the later chapters. You might be well well into the tutorial before you even look at it. Well, I decided that I need to find out how to use this quite quickly. So, again, mostly this is guesswork from my knowledge of other C-like languages. That's C and Java, for example, create classes and let you derive objects from them. So, I created a class called thing and I used this is the string data types. I said D does have a string data type, so I've G it a name.

field. I had to look up how to create a Constructor. It's using this keyword, and then you pass to its arguments. And here, the argument, the string argument, is used to initialize the name field. And I wanted then to have the name itself, the name field, private, so it's encapsulated, so the data is hidden, and to have accesses. And the way that I chose to do it was to have uh accessors called name. Now, even though these have got the same names, these two methods, they uh differentiate between them because they've got different argument lists. So I can assign a string using this one, and I can return a string, the string name, using that one. Now, I then descended uh another class room from thing. This again was guesswork because I've come across various different syntaxes of creating lines of descent. And so it turns out that indeed this colon is put between the new name and the ancestor class name. But again, if you wanted to, you know, if you couldn't figure that out just simply looking it up in some documentation.

we'll explain that very quickly. Now, the room inherits the name from The Thing class, and it adds on these integers: north, south, west, east. Those are the exits into other rooms. Then, this is its constructor. It takes all those arguments, and it calls super again. I guessed this from experience with other languages. Uh, it calls the super class, passing to it a name, and then it initializes these arguments. Now, down here, I just messed about. I mean, this code is all over the place, really, but that's a really important stage when you're learning a language. Just mess about. It doesn't matter if you muck things up. I mean, in fact, you should, because you're really trying to find your way around the language. So, I've created a new thing. I've used writing, which I've done before, and then I've created a new room. And now, I've written this. Uh, here, this is just a prompt character read the string that the user enters created a new thing. Now, s dodap. This is to do with how strings are

handled the difference between strings and uh character arrays. There is a distinction made so this a string has been read here, and I need it to be uh duplicated as a character array. I had to look that up. That was one thing that I wouldn't just guess. I I did look that up, and so this is the kind of process I go through when I'm messing around. I hit a problem. That's the stage at which I have to go to the documentation to look things up. I discovered that as expected, I can pass an argument like this, and an alternative syntax. I I just found this through messing around and trying it out, is to use it like a property in C, where you use this like a variable, even though it's actually a method, and assign the string the single argument to it. Um, the rest, I think, is fairly straightforward. Oh, the I wanted to display the number, the integer on the North side. Again, I had to look up how to convert an integer into a string representation, and I found that this is the way to do.

it two exclamation marks and string and in order to do that, I had to import std.com. So again, that was something I had to look up. Um, is there anything else that needs explaining here? I don't think so. Oh yes, there is one thing. I tried to make this private. Again, these are things I had to look at. How do you make sections of a class private or public? And so by putting private colon, I can declare a section of private variables here. And then these accessor, these methods are public. However, I discovered that I can actually, if I wanted my private variables underscore name, that shouldn't be available if it's private, should it? So I should have an error there. I'm expecting, but, uh, apparently not. So again, that's something I had to look up. Why is that privacy not being observed? It turns out that in D, even if something is private in a class, if it's all in the shared module, that's this single code file in this case, then it will be public, which is not what I want. So I had to find out.

next, how to create a module again. That's something I looked up in documentation. So here, I would say in my first, I guessed maybe 80% of the code, and I ran into a few problems, which I've mentioned. That's when I had to look up the documentation, right? So, this is my rewritten version. Here, I've added a module to hold my Thing and Room class in Visual Studio. That's done with right-clicking the project, and then you can click add and add a new item. Obviously, that's going to be different in other editors or IDEs. You can see I've just created a module called my classes, given it the name up here, and it's in a file called my classes. D. This is just the same code that I had in the previous version. I've still got string uncore name marked as private. Now, if I go into the main file, the file that starts the program, that just creates a room and it prompts me, sorry, it writes this prompt here, and it says you are in, etc., etc.

difference here is if I try to access that private field now I get this squiggly. It says that there's no property uncore name. And so that is how I've enforced the Privacy just by creating a new module and importing that module. Okay, so after that experimentation and now think I'm ready to start writing the very, very simplest possible Adventure game here. I want a map containing four rooms. I've already defined the room object as I've shown. The int variable defines the player's position, which starts off a zero. I've drawn out this little map. So r0 is the name of the first room. It goes east to room one. R1 South to room two, and that goes east to room three. And there are no exits in the other directions. I've then created the rooms. You can see in the four rooms down here. And I've added them to an array. So I've defined a room array called map to contain four rooms. And I've just added them one by. Now all of this has been

done with guesswork because I've used arrays in other languages. And if you've used C or Java or some other C-like language, you can probably make a good guess at how to do this. I might have made a few mistakes along the way, but it was fairly simple to rectify. Then I've just written this moveTo method so it takes a number, and that's the number of the room that to be moved to. And if it's minus one, minus one means no exit in that direction. Well, if it's minus one, I just display no exit. Otherwise, it updates the player's position, that's the pos variable, to the new room number. And it writes You have moved into and then it goes into it indexes into the map and it gets the name of the room at that position. Then there's my main function down here, that's what executes when the program runs. This is all fairly straightforward. I've got exit as an integer. First of all, it calls init. So init where

is that so that's this method. That's the method that first creates the rooms and the map okay so so it calls in knit then it writes that you are in well it's room zero because pause starts off as zero at the start of the game. Then I've got this do while loop again. I I looked up Loops in the doc documentation but I was guessing there would be something like do while as that's a common sort of loop so that executes the loop while this condition is true and the condition is that the player has not ENT entered Q the string Q uh to exit so not equals that's again guessed from my knowledge from other SE like languages uh switch case again that's very like in in other C like languages it's just a multiple choice so if the player enters the string s that's readed in from the command prompt up here if the player enters that string um and it's the string is n then I find the exit uh of at the end position the north position in the room the room is the uh

map is the room object at the current position, and it's the same for s, w, e, and the default is no exit so that should all work in principle. Let's see if it does. So South should go to oh there should have been a room there on East. I can't even use quit there is something wrong with my code so this is my other secret weapon before I go on that I should say you know that when I say I'm looking things up um I've got online documentation which I refer to and I'm going to be referring to that shortly because my assumption is that there is something wrong with the way that I've read this string the string is not being recognized as n it's not matching this uh and so on so let's see what's wrong so I'll do it again so let's enter s now that should match the string s but let's have a look at what s is looks like s ah but if I expand it using the

debugger. By pressing that arrow, I can see there are two characters. There's an S followed by the value 10. That's an ASCII code 10, which is a line feed, not a carriage return, which is 13. And so when I'm expecting it to match S down here, let me put another breakpoint down here. I'm expecting it to match S. It doesn't because I'm testing that the string is one character long. That's just a single S. Back to my documentation. Okay, so this is where I start looking things up. I've got this Programming in D reference here, and I'm looking for something to trim off. In many languages, it's called trim. I tried that and it didn't work. So I've gone to the documentation to see if I can find something else. And this is what I find. In D, the function that strips off the non-printing characters like spaces and carriage returns and line feeds is called strip. And I assign it back to a variable as shown in this

documentation. So that's all the documentation I looked up to get this to work. Let's try that. So according to this documentation, I should be able to call S equals strip s um. It seems happy with that. One other thing I've had to do, by the way, again, this is where you look in the documentation, is I've had to import std. string to get this to work. Let's see if that works. And right, this time the break point is hit. Let's have a look what S is. Y. Yeah. So this got rid of the Rogue character. Continue. And it's hit the case statement, but I'm expecting it to continue. Let's get rid of all these break points now so I can just continue watching the running program. Okay. So yes, I've moved into a new room East. There should be another room, and there is East again. Should be no exit, and there is West. And I can move around the game by entering the directions. And Q should quit because that's the test statement down here. The exits from this Loop so.

that's my first. I would say about 3 hours from knowing no D at all to writing a very simple ad object-oriented Adventure game. So I'm pretty pleased with that. That, in short, is how I go about learning a new language. Now, as I said, this has been about my approach to learning a new language. It's not a tutorial to D. Experienced D programmers will have much more effective and efficient ways, I am quite sure, of programming what I have shown than I used in this, uh, in this video. Because these are just my first few hours learning the language. So whether you're learning D or rest or Java or C or C or C++, whatever you're learning, what I really want to get across is a way of starting to learn that language without getting bogged down with thinking you've got to read every single chapter in an impenetrably long book, uh, or solve hundreds and hundreds of exercises. Anyway, I hope that's given you an insight into how I approach it and maybe you can take

something of use from this video. If you like this video, give it a thumbs up. And to make sure you don't miss any of my other videos, be sure to subscribe to my channel, ring the bell, and I'll see you again soon with something different.

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