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(upbeat music)

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Frank: In this video, I'll show you how to set up

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and use the integrated debugger in Visual Studio Code.

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So for this example, I'm going to use project two

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and I'm just gonna make one that'll change right here.

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I'm gonna initialize that number to 100

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just so we can see it in the debugger in a minute.

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So let's create this.

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What we're gonna do is we're gonna create

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a launch.json configuration file.

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First order of business is

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click on one of the main CPP files.

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Since I'm using project two,

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that's the one I'm going to select.

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So you can click on that file

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and then you're gonna come up to Run, Add Configuration,

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and it's going to ask you again, what's your environment?

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We're going to always be using C++ GDB/LLDB,

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so that's what I'm going to select.

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And again, I'm using mingw64 g++.

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I'm gonna select this guy right here.

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And we're gonna come over here.

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Don't worry about this.

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You could just click that little red square right here

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and get out of here.

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The important thing is,

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and we can come back over here as well to explore

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or just to clean this up a little bit,

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so the important thing is

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it has created a launch.json file for us

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and this is the one that's right here in the editor

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and this is the one that we're gonna configure.

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And the configuration here is pretty easy.

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There's just one entry we need to change,

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this one here on line 14, which is cwd.

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That's our current working directory.

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What we're going to do is we're gonna replace this

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with fileDirname

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and this time we're gonna grab the dollar sign

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and the curly as well.

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So we're gonna put that right in there, like that.

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That's it, so we're done with that.

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We can close up our launch.json.

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Now what we're going to do is we want to debug this program.

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So in order to debug the program, we need some break points.

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We need to tell the C++ debugger where to stop

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because otherwise it's just gonna run the program.

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So it's gotta stop so that we can examine variables,

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we can look at our logic,

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and we can step through the code one line at a time

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so that we can follow our logic and find mistakes

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or verify that what we did was correct.

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So let's do that.

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We can do this a couple of different ways.

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First of all, make sure that we've got this selected,

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main.cpp, in whatever project we want to debug.

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In this case, we're debugging project two,

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so make sure your default has selected main.cpp.

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Then we can come up here to Run, Start Debugging,

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or we can come over here on the left side here.

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Again, select main.cpp,

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and click that bug right there, right, run and debug.

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That's what I'm going to do.

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And now what we need to do

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is we need to add a break point to our code.

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And you can see over here in the gutter here,

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I'm sliding through

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and you can see that red dot coming around.

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That's a break point.

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So if I wanna put the break point right about there,

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it'll light up.

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It'll all show up down here

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that says we've got a break point.

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Visual Studio Code has a little glitch sometimes

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where it captures break points from a lot of the projects

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instead of just the one you're working with.

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And an easy way to deal with that is just to

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before you start debugging

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just come over here and click that X right there.

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That'll clear up all the break points everywhere

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and then you could just set the break point where you want.

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So I'm gonna set the break point again right there.

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So now that we've done that, we're gonna run the program

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and what we can do is we can come up here

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and click on that little green arrow

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and you'll see what happens.

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The debugger comes into play.

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A lot of things seem to happen all at once.

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We've got this little menu bar right here,

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this bar of icons that allows us to step through our code

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one line at a time, stop the code,

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rerun the code, and so forth.

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And we also have this variables window

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that popped up over here on the left.

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And this is showing the values of our local variables.

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Look at num, it's initialized to 100,

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so it shows up right over here.

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Also, we can use our cursor and just hover over num here

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and you can see its value is 100.

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So it lets us inspect the value of that variable

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as we're running the code, which is really neat.

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So right here, this yellow line,

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that shows you where I'm at in the programs.

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So you could see that yellow bar shows us

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exactly where our program is.

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This line has not executed yet.

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So if we want to execute it,

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we can come over here and step over it or step into it.

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And I'll talk about all this in the course.

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And in this case, I wanna step over it

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and notice the output came out down here.

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So that's the line we're at.

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So I'm gonna step over it again

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and now we're gonna get the input from the user.

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So let's say I type in 1,200.

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Now as soon as I press Enter,

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that 1,200 will be read into num, right?

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So my variables should change.

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I'm gonna press Enter

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and now notice that num up here is 1,200.

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I can also hover over num over here and it's 1,200.

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So this is a really, really powerful feature.

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Debuggers are great. We use them all the time.

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We don't overuse them.

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If it's a really simple program and you've got simple logic

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and you can test your code easily,

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there's no real need to debug it,

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but sometimes it comes in really handy

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when we're trying to figure out a problem

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or looking at some really complex logic

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that we wanna walk through step by step.

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So that's it.

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Now, if we wanna stop the program,

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we could just click that little red box right here to stop.

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If we want to just continue full blast

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and skip all the break points,

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we can click that little arrow right here

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or we could just click on it a few times

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until the program ends.

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And let me just stop it here

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so you can see what that looks like.

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So I stop it.

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So now it's gone, notice it's changed back to blue down here

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and I can come back to my Explorer

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and I can see everything that I'm doing.

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So there you go, that's how the debugger works.

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In the next video, what I'm going to do

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is I'm gonna show you how to use Visual Studio Code

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with the source code that I've provided for the course.

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The source code that I provided for the course

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is in the format of CodeLite projects, but that's okay.

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They'll work in Visual Studio Code as well,

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and I'll show you exactly how to use them in the next video.