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In this video, we'll go over the steps necessary to create,

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build and run

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a c++ program on ubuntu Linux

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using only a text editor in the command line.

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So in this video, we won't be using any integrated development environment.

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First of all,

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I've created a folder on my desktop called cpp projects.

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And in that folder, I've created another folder called project1.

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This is where we're going to store our c++ program.

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In this case, it's just going to be a main, a real simple test.

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So I'd like to close this up

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and the first thing we need to do is we need some sort of editor to type in our program.

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Now on Linux, we've got gedit.

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So I could just come to search my computer and type gedit.

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And we can use that text editor which is a fine text editor. It's real simple.

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It comes with your installation.

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There are many other text editors and programmer text editors that you can use,

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like brackets,

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atom and many others but this one is already here.

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So we may as well use it and it works just fine.

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I've gone ahead and gone to edit preferences.

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And I just turned on line numbers, and you can set all kinds of different settings that you like.

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I made the font also a little bigger so you can see it.

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So it may look a little different when you start yours.

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So the first thing we want to do is we want to write the c++ program. So let's do it.

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Include

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io stream just like we've done before.

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I'll leave a space and then I'll say int main,

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two parentheses, the open curly,

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and I'll close the curly while I'm at it.

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And now we'll just say we could just press tab.

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We'll say std::cout.

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The insertion operator which is the two << signs,

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break together with no spaces. And I'll say "Hello

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Ubuntu command line".

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We'll close the string.

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We'll put another insertion operator,

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and let's put a new line at the end that way our cursor will go to the next line when we do the output.

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And that's e-n-d-l followed by a semi-colon.

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And then we return 0 just like we always do.

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That's it. That's our c++ program.

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Now it's important that we save this with a .cpp extension and not

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a txt extension.

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Z++ compiler does not like txt extensions. And you're going to get all kinds of

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weird errors.

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Okay. So let's do that. Let's go to file,

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save as.

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We'll find where we want to save it. We want to save it to our desktop,

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cpp projects, project1.

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That's where we would like to save it. And I'll give it the name as main.cpp.

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Now you'll notice a couple of things. When I name the file cpp,

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the editor is smart.

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So it realizes that this is not a regular text file. It's a c++ text file,

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so I'll save it. And notice what happened here.

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Notice the color coding, it knows c++.

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Again, it's not an integrated development environment.

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So it doesn't have a lot of hooks to the compiler and so forth.

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But you can see that now it's really helping me

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because I can see that my string is terminated.

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For example, if I get rid of that guy,

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then that's black and it shouldn't be black, it should be a magenta color.

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So again, I'm going to press ctrl s to save that file.

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Now we'd like to compile and run it.

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So in order to do that, we need to open up a terminal.

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So I'll come up back up here, and I'll say terminal.

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And that'll open up a terminal, which I'll pull down just right

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by here so we can run them together.

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Now one of the things that you'll notice is that

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if you do a pwd, which prints your working directory,

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I'm in home Frank.

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I don't want to be in home Frank. I want to be in this directory, right up here that you can see desktop,

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cpp projects, project1.

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So I need to change into that directory. We can use a cd command

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to change directories. So I want to go to my desktop,

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and you can press tab for auto completion,

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and press enter.

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Then I want to press -- then I want to type cd

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cpp projects.

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And then finally, project1.

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And you could do this all in one line if you like. I just did it in three steps.

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So now I'm in the correct directory.

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If I want to know what's in that directory, I can just type LS, which gives me a listing of the directory.

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And you can see that my main cpp file is there.

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That's the one that I want to compile.

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So let me make this thing a little bit wider just you can see what I'm typing here.

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So the first thing I want to do is I want to execute the compiler.

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So I want to say g++, that calls the compiler.

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That's the gnu c++ compiler.

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And I want to set some options. These are the same options that we would set with the IDE.

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Here, we're just going to set them as switches right on the command line.

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So I'm going to say Wall,

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that turns on all warnings.

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Then I want to say -std=

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c++ 14,

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that's going to use the for the 2014 c++ standard,

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which is the latest one that's out there.

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Now we supply what do you want to compile? Well, I want to compile the main.cpp file.

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Main.cpp. That's it. So it's going to execute the compiler,

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turn on all warnings,

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use the latest standard and compile that one file, main.cpp.

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I'll press enter.

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I got back no messages, which is good as they say no news is good news.

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If you have errors, it'll tell you. If you don't, it'll be nice and quiet.

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At this point, I'll do an LS again to see what's in our directory.

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And you can see that it's created a file called a.out.

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That's the common normal file,

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executable file that's created when you don't say hey create main or

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create some other name.

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To run it, you just type ./a.out.

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And there you go. It says hello ubuntu command line, exactly what we typed up here in our program.

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If you don't want the a.out, and you want your own executable,

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then you could type that in and I'll show you how to do that.

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What I'm doing now is I'm pressing the up arrow

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and the down arrow and you can go through what you've typed in that way you don't have to type it all in again.

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So you want to go back to the statement where you compiled and just type a

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-o and the name of the file that you want to create.

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So in this case, let's just say main. That'll be my executable.

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I'll press enter. I'll do LS again.

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Now you can see that there's a main file right there.

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And I can now run main. And I get the same output.

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Okay. Simple as that it really is very straightforward.

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Now one of the things that you have to keep in mind.

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Since this is not an IDE, you've got two things going on here separately, right?

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You've got your editor here and your command line tool here.

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They're not really synced together. So you're the one that's syncing them together.

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So if I remove the semicolon from my text editor

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and I compile again, I expect an error, right?

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I didn't get an error. The reason I didn't get the error was because I never saved the file.

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You have to be sure to save the file and then compile.

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The IDE sort of handle that magically behind the scenes.

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They realize that you've made a change. So it's going to compile the latest changes you made.

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This is different since they're not in sync.

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So you want to be sure that you can come up here

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and save file. Save or control s.

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Now I've saved it, now I compile, now I see the error.

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So you can see the errors it's expecting a semicolon,

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which I can replace if I get rid of this quote mark

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and ctrl s. I'm saving again.

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Now I run. Now I'm going to get a different error,

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something about a terminating quote character is missing.

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So I can put that back in,

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ctrl s and save and compile again.

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And we can run main one more time.

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That's it. So that's it. That's pretty straightforward.

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These are the steps necessary when you have a plain text editor and the command line.

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If you cannot install an IDE for some reason,

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maybe you've got minimal hardware requirements, you just don't like IDEs or

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you find them too confusing,

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don't let that stop you from learning c++.

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You can still use a simple text editor like this

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and a command line tool and you can see the command, you can see the command right there.

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It's really, really straightforward.

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If you've got multiple c++ files, which we will later on in the course,

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you just type them all in here file1.cpp, file2.cpp and so forth.

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It'll compile everything, link everything and run it for you.

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Many times you're if you're a consultant and you're working out there, you'll show up at a place,

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and there's no IDE. You know you're working as a consultant,

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all you need is an editor and a command line, and you're in business.

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Okay. So that wraps up this video.