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(upbeat music)

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(keyboard types)

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Frank: Welcome back.

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In this video, I'm going to show you how

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to set up the debugger so that we can debug C++ programs

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in Visual Studio Code.

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The debugger is a great tool that allows us

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to execute our code one line at a time.

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We can inspect variables as we do that.

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Let's use the same project that we wrote

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in the previous video, and I'm gonna debug project two here.

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I'm just gonna make one little change to it.

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I'm gonna initialize favorite number to a 100

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just so we can see it, and see it when it changes.

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All right, so where do we start? Well, it's pretty easy.

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You just select any main.cpp file.

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What we're doing now is we're configuring the debugger.

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I'm gonna select main.cpp, then I'm going to go up to Run,

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and add a configuration.

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I'm going to select C++ GDB and my g++ compiler again.

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Now, you'll see this little menu bar pop up.

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Just click that little red box to stop the debugger

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and we'll finish configuring it.

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I'm going to close this window down here

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to give us some more room.

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You can see that a new file was created.

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It's called launch.json.

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This is the one that we're gonna modify slightly

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to get our debugger to work.

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The most important thing to do here is

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we want to change line 9, which is the type,

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and we want to change that from cppdbg to lldb.

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Now, when we do that,

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you'll see that we have some errors pop up here

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on lines 13, 15, 16, and 17.

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We want to delete those lines completely.

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Let me get rid of that.

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We'll get rid of these three lines as well.

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That's what we've got now on line 13.

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Cwd should be fileDirname.

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If it's anything other than that, be sure to change it

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to fileDirname, and that's it, we're done.

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Again, make sure there's no squigglies

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and no errors in here.

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I just save that

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and I'm going to close it because we're done with it.

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Now, we're ready to debug.

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To start the debugger,

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select the file that you want to debug.

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In this case, I want to debug main.cpp in project two.

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If I wanted to debug project one,

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I would click on main.cpp in project one.

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I want project two's main.cpp, so I've just selected it

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Here it is in my editor.

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To start the debugger,

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you click on this bug icon right here, Run and Debug.

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I'll do that now.

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You'll notice a couple of things happen.

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Well, one is you have this play arrow up here,

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and you have this information area where you have variables,

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and watches, and call stacks, and breakpoints.

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I'll cover these during the course.

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I'll cover them in CodeLite in the course,

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but it's the same concept in Visual Studio Code.

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What we need to do first is set a breakpoint.

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This is the place where the debugger is going

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to stop executing our code.

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You can do that right over here on the left side.

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If you just hover over this left gutter here.

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You see that red dot that keeps popping up?

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Well, you could just select that.

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Let's say that I wanted to stop right on that line.

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Now when the debugger starts executing,

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it's gonna run the program and stop here,

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and then we can control it from there.

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Also, notice that when I select that breakpoint,

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it shows up down here.

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Right, main.cpp's breakpoint in project two.

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Now, Visual Studio Code has a glitch

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where sometimes all the breakpoints

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and all the projects show up here.

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My recommendation is when you start your debugging,

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as soon as you click on that bug icon,

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just come down here and click that X

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if there's anything there.

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That clears out all the breakpoints everywhere.

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Then, you can just come back up and select your breakpoint,

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and you're good to go.

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Once you're ready to start debugging, we click

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on that green play button right up here on the top left.

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When I do that, you see this little menu option

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here comes up with these icons that control the debugger.

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The bottom bar down here turns orange.

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This area right here is where your variables show up.

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You can see my favorite number variable is a 100,

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and that's exactly what I initialized it to.

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We can also hover over our variable names just like that.

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You can see the 100 pop up.

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That's the value and that's the current value.

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If we change it, that number's going to change.

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You can see that line six executed right down here

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in the terminal: Hello from project two.

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Now, what I can do is I can click these buttons,

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and I'll explain these buttons during the course,

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but this one right here just steps over the code.

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It executes that statement.

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If I want to execute that statement,

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now, the program is basically waiting

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for us to type something in, right?

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Right here, we have to enter our favorite number.

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I'm gonna enter in something other than 100

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so that we can see favorite number change.

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Let me type in 45 and press Enter.

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You can see now that the playhead is here on line nine.

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Line nine has not executed yet,

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but also I noticed I entered 45,

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but look what happened over here

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on the top left in my variables: favorite number is now 45.

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Again, I can hover over at any word that it's being used

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to see its value.

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This is really handy.

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Sometimes programming gets really complex.

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It's very helpful to be able to execute your code one line

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at a time, and see your variables,

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see the results of your calculations visually.

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It can be very, very useful.

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When we're done, we can just continue the program

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or we can stop the program right here.

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In this case, I'm just going to continue.

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You can see it says here, "Your favorite number is 45."

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At this point, we're done. This bottom bar turns blue again.

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If we want to continue editing and so forth,

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we can just click Explorer and go right back to our files.

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So that's it.

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At this point, we've set up Visual Studio Code

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for building a task.

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We know how to execute our executable,

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and we know how to debug our project.

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In the next video,

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I'll show you how we can use the source code

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that I provide for the course within Visual Studio Code.

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I'll see you there.