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‫So now we're going to build our Stack constructor.

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‫And since we're going to implement our Stack as a linked list, first we need to create a node.

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‫And we had said that this node is similar to an unordered map.

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‫And that value in next would be the member variables and our node class where value is an integer and

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‫next is a pointer to a node.

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‫And then for the constructor, for our node, we pass it a value and then we say this value equals value.

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‫And then we set next, which is a pointer to null pointer.

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‫So this is identical to our node class for a linked list.

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‫So now let's start building our stack class.

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‫We'll start by creating our member variables, which will be set to private.

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‫And as I have mentioned previously, you don't have to put private in here because classes are by default

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‫private.

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‫But I like to explicitly put that in there because I think it makes things more readable.

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‫And our class member variables are going to start with TOP, which is the equivalent of head in a linked

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‫list.

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‫And as we discussed in the last video that the equivalent of tail would be bottom, but because with

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‫a stack you're only adding or removing from the top, you don't actually need this.

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‫So I'm going to remove this and then we're going to keep track of the height and that'll be an integer.

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‫And so now we can start building out the constructor for our stack.

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‫The constructor will be public and we'll start that out like this.

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‫And I'm going to just focus on this constructor code for now.

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‫So the first thing we'll do is create a node with the value that we passed the Stack constructor like

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‫this.

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‫Then we'll set top to be equal to that new node like this.

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‫And because we have one item in the stack will set the height to be equal to one.

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‫But since this is a stack, I'm going to take that node and turn it like this.

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‫So let's take this constructor and put it back in with the rest of our code like this.

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‫And now we're going to flip over and look at this code and nv's code.

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‫So there is our node class there and I'm going to scroll up and this is what we just created in our

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‫stack class.

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‫But just like I did with link lists and doubly linked lists, I have also created print stack, get

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‫top and get height.

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‫So I'm going to scroll up again.

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‫And in our main function this creates that new stack with a new node with a value of four.

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‫And then with these three lines I'm going to run, get top, get height and print stack.

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‫So now I'll run this and you can see that top points to that node with a value of four and the height

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‫is one.

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‫And then with print stack that just prints out that one node with a value of four.

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‫So that means we have a working stack constructor.