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362. Stack Java Class - Explained
Earlier we saw about Stack and its implementation using Linked List. Java has a built in class for Stack. In this article we will discuss about it in detail. First brief about Stack.
What is Stack??
- Stack is an abstract data type (ADT) and very useful in programming.
- In computer science, a stack is an abstract data type that serves as a collection of elements.
- Majorly all the operations are done at only one end of the stack which is top of the stack.
- The order in which elements in stack are stored is with LIFO (Last-in-First-Out) manner. This means the element inserted last will be removed first.
See the diagram below for more understanding.
Operations on Stack
push(): Push the element to the top of the Stack. Time- O(1)
pop(): Remove the element from the top of the stack and returns that element. Time- O(1)
peek(): Returns the top element of the stack without removing it. Time- O(1)
isEmpty(): Return true or false, based on stack is empty or not. Time- O(1)
getSize(): Return the size of the stack. Time- O(1).
Output:
Inserting 1 into Stack. Inserting 2 into Stack. Inserting 3 into Stack. Popping Element from stack Popped Element: 3 Popping Element from stack Popped Element: 2 [1] Inserting 6 into Stack. peeking Element from stack Peeking Element: 6 [1, 6] Is Stack Empty: false Stack Size: 2 Stack Size: 2 Searching element 5 in Stack 5 not found in Stack Searching element 1 in Stack 1 found in Stack at position: 2