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OK.

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Welcome to this next video about stacks and queues today, we are just actually going to go over.

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The syntax of implementing this, all you see that I've already included stack and queue up here in

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addition to extreme, because I'm just going to need to print some stuff out so we can verify what it

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is like when we actually move through and to these data structures and how that looks.

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So to do this, I'm actually just going to take some user input from the console.

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And of course, I just mean, like a quick little file here.

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You can make this in the terminal or C line if you make a new project, but it's just going to be this

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one file may not CP.

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So I'm going to go ahead and make a char and clicks.

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This just going to be like a word that we're going to read in, and we'll store each character in these

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data structures and make the stack.

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It's just like a vector.

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Pretty much so I'm putting in the type here.

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I'm going to call it char stack of type char and then name it my stack.

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Same thing with CU Bay.

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Simple, I call this my cue and then I'm just can make a little like do while loop here.

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So I'm going to see in and I'm just going to, you know, skip whitespace.

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So if you haven't seen this before or this just doesn't skip the doesn't ignore whitespace characters.

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So that way, you know, at the end of the line, I'll press enter and we'll just take in the characters

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and it'll be all good.

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So and then I'm going to read into input.

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And then what we're going to do is use this push that I talked about.

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So it's just like calling a function like this.

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My stack dot push and we'll push the input to it.

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And so just remember that what this is doing is it is adding a new character on the top of the stack,

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so it's growing up, we're just stacking stuff on top of stacking characters.

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And this adds a new character on top.

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And would do the same thing to the Q or I do like my huge push, but this is similar to like a vector.

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It's pushing back, so it's actually adding to the end of the queue.

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And then I'll finish this hour by putting the condition, I'm just going to say, while the input is

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not equal to a new line, so I actually need to add that backslash backslash there.

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All right.

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So.

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It makes sure I don't know, I have that extra thing there.

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I'm going to go ahead and just print it out now, print out the stack in a while loop and then separately

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print out the Q.

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So I'm going to say, wow, not my stack.

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And what I can do is use another function here that checks if it's empty.

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So I'm going to do.

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While not my stack got empty, so while it's not empty, I'm just going to go ahead and print out the

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top.

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So just like we saw in that theoretical lecture, I'm going to be calling that top function to reference

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the thing at the top of the stack will print that thing out, and it'll just print out side by side.

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And then what I'm going to do afterwards is do the part function.

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So my stack that pop and this will pop that top character off after we've printed it out there on Line

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18.

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All right, cool, so I'm going to go ahead and like, just do it in line here and then I will do the

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same thing for the Q, so we have the same function available for the Q, where I can do well, not

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make you empty.

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So as long as the queue is not empty, the loop and then same thing, I'm going to use that front function.

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So my cue Typekit front and this will reference the thing at the front of the queue afterwards.

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Same thing is Stack.

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I'm going to do my Q Dot pop that will pop the.

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The first item, so the leftmost oldest item off of the Q, so after that, I'll do the same thing and

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just put it in line.

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And then we should have our return zero here.

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So I think that we are all good, this should just if it works correctly, it'll ask us for some input

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and then we will see.

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The traversal of the stack, which is the most recent thing, so first in I'm sorry.

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Last in, first out for the stacks of the most recent thing will be the first thing that we're printing

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out the first character.

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So that should generate if we're taking the most recent thing after we've entered it, it will be reading

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it from right to left, so essentially backwards and then the queue since it's the first in, first

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out.

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So the oldest thing is the first out, then it should be basically left.

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Since we're writing left to right, the oldest character would be the left most, so it should print

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in order.

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So let's see if that actually happens.

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Cool.

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So I'm just going to say.

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I'm just going to say it's a beautiful day.

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How about that?

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OK, and there we see when we go, we go through these stack first.

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And it prints it out backwards like we were just talking about.

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And then we go through the queue and the queue actually prints it out in the correct order there.

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So just like a basic thing to illustrate the differences between these two containers, less data structures

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and.

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It just needs to be introduced enough for you to feel comfortable using them in this next section,

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so hopefully this is enough for you to understand.

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Of course, go ahead and play around with them more head to something like C++ dot com and look up all

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the functions that you can use with them.

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I just covered the most important three functions there.

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And also, this empty kind of just adds a little extra since we're living through.

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All right, so I hope you enjoyed that and it was informative.

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It should be pretty simple.

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We're not really going too deep into these, but we will be using them for a lot of algorithms and they

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are very useful.

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And so I will see you in the next lecture when we start using these for some different things.