Java Essentials - The stack class in java

In this video we are discussing the stack class in Java

We know that stack is one data structure which supports the lasting fast-out or fast-in-out data structure

This stack class is a sub-class of vector. So let us go for more discussion on it

So the stack is a sub-class of vector and that implements a standard last-in fast-out stack

a stack has all the methods of the vector class but it has got its own methods too so all the

methods can be accessed from the stack class which was there in the vector so but stack class is

having some separate methods defined within it the first one is the push to insert into the stack

at the top position to insert some element at the stack at the top position we're having the

method called pop delete the top most element from the stack then we're having this

pick then return topmost element not deleting it just returning the topmost element

we having this empty to check whether the stack is empty or not we having this search and search elements in the stack content so these are the very important methods which you use in our stack when you will when you be writing our java

code so now let us go for one practical demonstration to give you a better idea how this stack

class can be written can be written in our java code and how the program will produce our

desired outputs so here is the demonstration for you we have defined one stack object

stack class object that is a my stack which will hold the integer wrapper class

objects as its members so is the new stack constructor so now how to put our

elements that is the integer objects within this my stack stack object here so

stack is the name of the class my stack is the object under the stack class so the

method is push with the help of push we can we can put our integer objects

within this my stack object so you can find that my stack dot push 10 then 20 then 30 then 40 then 50 so 50 will be at the top

and 10 will be at the bottom here so now we are going to print the size of this my stack so as we have pushed five such elements so that why five such integer class objects so that why the size stack size is five here now we

going to introduce one method there is a peak this particular peak method

will actually check the topmost element of the stack but it will not delete it

from the top it will only just check the current content of the topmost element of

the stack here so when you are going for this peak and later when you are printing

that is a my stack dot pick method we are printing the current content whatever has been

picked it is printing 50 here so now using this while body so not my stack dot is empty

so is empty will be returning true and when the is empty will be returning true

then I should come out from this while so that's why I have used the knot operator

there so true knot of true will become false so it will come out from this while

So that why while not my stack dot is empty so that is another method you are getting defined under the stack class here so that is our is empty and here you can find that is empty is a method which returns the bullion and it returns the bullion it is defined under the actual class is a vector and is empty is the method and this vector is under the package java dot util so as this particular

while will be executing until the stack is getting empty so the while will get execute and each and every iteration will be picking up one of the elements from the stack so my stack dot pop is the respective method which returns this integer class of the

we can because here we are having this my stack we defined that it will be holding

the integer wrapper class objects and the method is a the public e and then pop

removes the object at the top of the stack and returns that object as the value

of its of this function so in this way it will return so let me go for the

output you can find that 50 has been returned at first then 40 then 30 then

20 and then the bottom most element then will be returned at the last

and then my stack dot is empty will return true not of true will become false so it will come

out from this while loop in this way in this particular demonstration we have

discussed that how to deal with the stack class objects in our Java code thanks

for watching this video