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Learn javaScript

I recently started watching Essentials of javaScript by DoriSmith @ Lynda.Com, It’s very interesting, easy to understand and helpful like many other video tutorials at Lynda.Com.

Video tutorials are very easy to follow, productive and easy to grasp. The only problem I find with video tutorials is, when you get stuck or have some doubt few days after watching the tutorial, it’s hard to refer back. So, its always good to prepare some notes of important points which you can refer back easily. I’m going to share my notes here as I go along, I hope you find it use full.

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Stacks are linear data structures. This means that their contexts are stored in what looks like a line (although vertically). This linear property, however, is not sufficient to discriminate a stack from other linear data structures. For example, an array is a sort of linear data structure in which you can access any element directly. In contrast, in a stack, you can only access the element at its top. In a stack Last thing In is the First thing Out. Thus, we say that a stack enforces LIFO order.

One disadvantage of implementing stack using an array is wastage of space. Most of the times most of the array is left unused. A better way to implement stack is by using a linked list. By using a single linked list to implement a stack there is no wastage of space.

Implementation of stack using a linked list

/*
A simple implementation of linked list in C plus plus (CPP/C++)
*/
/*
Compiler used: g++
*/
#include<iostream>
using namespace std;
struct node{
	int data;
	node *next;
	};
//This function pushes data(node) to the stack
node * push(node*,node*);
//This function pops data (node) and returns pointer to the poped node
node * pop(node*);
//This function shows the stack
void show_stack(node*);
///These two global variables will help us track the start and end of the list
node *f,*l;
main()
{
	int i,ch;
	f=l=NULL;
	cout<<"\t 1 to push"<<endl;
	cout<<"\t 2 to pop"<<endl;
	cout<<"\t 3 to show stack"<<endl;
	cout<<"\t 0 to exit"<<endl;
	while(1)
	{
		cout<<"Enter your choice:";
		cin>>ch;
		switch(ch)
		{
		case 1:
			{
			if(f==NULL)
			l=f=push(f,l);
			else
			l=push(f,l);
			break;
			}
		case 2:
			{
			cout<<"popped:"<<pop(f)->data<<endl;
			break;
			}

		case 3:
			{
			show_stack(f);
			break;
			}
		case 0:
			break;
		default:
			cout<<"Please enter a proper choice"<<endl;break;
		}
		if(ch==0)
		break;
	}
}
node * push(node *f,node *l)
{
	node *n;
	n=new node;
	cout<<"Enter data:";
	cin>>n->data;
	n->next=NULL;
	if(f==NULL)
	{f=l=n;return f;}
	else
	{
		l->next=n;
		l=n;return l;
	}

}
void show_stack(node *f)
{
	cout<<"showing data"<<endl;
	node *guest=f;
	while(guest!=NULL)
	{
		cout<<"\t"<<guest->data<<endl;
		guest=guest->next;
	}
}
node * pop(node *f)
{
	node *guest,*lb;
	guest=lb=f;
	while(guest->next!=NULL)
	{
		lb=guest;
		guest=guest->next;
	}
	lb->next=NULL;
	l=lb;
	return guest;
}
		

Download the program: Implementation of stack using a single linked list

The simplest kind of linked list is a singly-linked list , which has one link per node. This link points to the next node in the list, or to a null value or empty list if it is the final node.A singly linked list’s node is divided into two parts. The first part holds or [...]