Queue (enqueue,dequeue,display) Data structure

Friday, 28 October 2016

Queue

FIFO Rules, That is First in First out

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	/******************************************************
	QUEUE C++
	AUTHOR URI:https://mostafa.itnishi.com
	******************************************************/
	#include<iostream>
	#include<conio.h>
	#include<stdlib.h>
	#define SIZE 5
	using namespace std;
	int q[SIZE],front=0,rear=0;
	int main()
	{
	int ch;
	void enqueue();
	void dequeue();
	void display();

	while(1)
	{
	cout<<"\n 1. add element";
	cout<<"\n 2. remove element";
	cout<<"\n 3.display";
	cout<<"\n 4.exit";
	cout<<"\n enter your choice:";
	cin>>ch;

	switch(ch)
	{
	case 1:
	enqueue();
	break;
	case 2:
	dequeue();
	break;
	case 3:
	display();
	break;
	case 4:
	exit(0);
	default:
	cout<<"\n invalid choice";
	}
	}
	}
	void enqueue()
	{
	int no;
	if (rear==SIZE && front==0)
	cout<<"queue is full";
	else
	{
	cout<<"enter the num:";
	cin>>no;
	q[rear]=no;
	}
	rear++;
	}
	void dequeue()
	{
	int no,i;
	if (front==rear)
	cout<<"queue is empty";
	else
	{
	no=q[front];
	front++;
	cout<<"\n"<<no<<" -removed from the queue\n";
	}
	}
	void display()
	{
	int i,temp=front;
	if (front==rear)
	cout<<"the queue is empty";
	else
	{
	cout<<"\n element in the queue:";
	for(i=temp;i<rear;i++)
	{
	cout<<q[i]<<" ";
	}
	}
	}

view raw queue.cpp hosted with ❤ by GitHub

	/******************************************************
	QUEUE C++
	AUTHOR URI:https://mostafa.itnishi.com
	******************************************************/
	#include<iostream>
	#define maxi 1000
	using namespace std;
	class qqueue{
	int a[maxi];
	int f,r;
	public:
	void initialize();
	void enqueue(int val);
	void dequeue();
	void display();
	};
	void qqueue::initialize(){
	cout<<"Empty Queue is created :D";
	f=r=-1;
	}
	void qqueue::enqueue(int val){
	if(r==maxi-1){
	cout<<"\nQueue Overflow..";
	}
	else if(f==-1 && r==-1){
	f=r=1;
	a[r]=val;
	}
	else{
	r++;
	a[r]=val;
	}
	}
	void qqueue::dequeue(){
	if(f==-1 && r==-1){
	cout<<"\nQueue is already empty..";
	}
	else if(f==r){
	cout<<"\nThe dequeued element is.."<<a[f];
	f=r=-1;
	}
	else{
	cout<<"\nThe dequeued element is.."<<a[f];
	f++;
	}
	}
	void qqueue::display(){
	int x;
	if(f==-1 && r==-1){
	cout<<"\nThe Queue is empty..";
	return;
	}
	cout<<"\nThe Contents of the Queue is..";
	for(x=f;x<=r;x++){
	cout<<a[x]<<" ";
	}
	}
	int main()
	{
	qqueue q;
	q.initialize();
	int ch,val;
	cout<<"\nChoice: \n1)Enqueue \n2)Dequeue \n3)Display \n4)Exit";
	while(1){
	cout<<"\nEnter your choice..";
	cin>>ch;
	if(ch==1){
	cout<<"\nEnter the element to be enqueued..";
	cin>>val;
	q.enqueue(val);
	}
	else if(ch==2){
	q.dequeue();
	}
	else if(ch==3){
	q.display();
	}
	else{
	break;
	}
	}
	return 0;
	}

view raw queue2.cpp hosted with ❤ by GitHub