Data Structures : Stack

Stack is the data structure that can be logically through as Linear Data Structure. The basic implementation is called as LIFO ( Last In First Out ) way.




 







There are three operation can be perform in a stack data structure. 

1. Push ( Insertion of an element )
2. Pop ( Deletion and return of top element )
3. Peek (Return of top element, just pick and see what it is.)

Before going to the implementation lets look a Demo by Y. Daniel Liang.

 

	package com.nifrasismail.Stack;
	public class MyStack {
	private int size;
	private int[] StackHolder;
	private int top;
	public MyStack(int size) {
	this.size = size;
	StackHolder = new int[size];
	top = -1;
	}
	public void push(int element) {
	if (!isFull()) {
	top++;
	StackHolder[top] = element;
	}
	}
	public int peek() {
	return StackHolder[top];
	}
	public int pop() {
	return StackHolder[top--];
	}
	public Boolean isEmpty() {
	return (top == -1);
	}
	public Boolean isFull() {
	return (top == size - 1);
	}
	}

view raw MyStack.java hosted with ❤ by GitHub

	package com.nifrasismail.Stack;
	public class UseStack {
	public static void main(String[] args){
	MyStack S = new MyStack(20); //[] top=-1
	S.push(25); // [20] top =0
	S.push(35); // [20,35] top=1
	S.push(22); // [20,35,22] top=2
	System.out.println("Current Peek Value is : "+S.peek());
	S.push(99); // [20,35,22,99] top=3
	S.push(82); // [20,35,22,99,82] top=4
	S.pop(); // [20,35,22,99] top=3
	S.pop(); // [20,35,22,99] top=2
	while(!S.isEmpty()){
	System.out.println("Poped Element "+ S.pop());
	}
	}
	}

view raw UseStack.java hosted with ❤ by GitHub