Double-ended queue using c language

Answer 1

/* c++ program to implement double ended queue using doubly linked list with templates*/
#include
#include
#include
template
struct node
{
t data;
node *llink;
node *rlink;
};


template
class dequeue
{
private:
node *front,*rear;
public:
dequeue()
{
front=rear=NULL;
}


node *getnode()
{
node *newnode=new node;
newnode->llink=NULL;
newnode->rlink=NULL;
return newnode;
}


void insfrnt();
void insrear();
void delfrnt();
void delrear();
void disfrnt();
void disrear();
};


template
void dequeue::insfrnt()
{
node *newnode=getnode();
cout<<"Enter The Element That Has To Enqueued At The Front"<cin>>newnode->data;
if(front==NULL && rear==NULL)
front=rear=newnode;
else
{
newnode->rlink=front;
front->llink=newnode;
front=newnode;
}
}


template
void dequeue::insrear()
{
node *newnode=getnode();
cout<<"Enter The Element That has to be Enqueued at the Rear"<cin>>newnode->data;
if(front==NULL && rear==NULL)
front=rear=newnode;
else
{
rear->rlink=newnode;
newnode->llink=rear;
rear=newnode;
}
}


template
void dequeue::delfrnt()
{
if(front==NULL)
cout<<"Dequeue Underflow"<else
{
node *temp;
temp=front;
if(front==rear)
front=rear=NULL;
else
{
front=temp->rlink;
front->llink=NULL;
}
cout<data<<" is the element deleted from the dequeue"<delete temp;
}
}


template
void dequeue::delrear()
{
if(rear==NULL)
cout<<"Dequeue Underflow"<else
{
node *temp,*prev;
temp=rear;
if(front==rear)
front=rear=NULL;
else
{
rear=temp->llink;
rear->rlink=NULL;
}

cout<data<<" is the element deleted from the dequeue"<delete temp;
}
}


template
void dequeue::disfrnt()
{
if(front==NULL)
cout<<"Dequeue Underflow"<else
{
node *temp;
temp=front;
cout<<"front";
while(temp!=NULL)
{
cout<<"->"<data;
temp=temp->rlink;
}
cout<<"<-rear"<}
}


template
void dequeue::disrear()
{
if(rear==NULL)
cout<<"Dequeue Underflow"<else
{
node *temp;
temp=rear;
cout<<"rear";
while(temp!=NULL)
{
cout<<"->"<data;
temp=temp->llink;
}
cout<<"->front"<}
}


void main()
{
dequeue dq_int;
dequeue dq_float;
dequeue dq_char;
int choice;
do
{
clrscr();
cout<<"DEQUEUE :"<cout<<"\t Double Ended Queue (abb :- deque ; pronounced as deck) is an abstract data structure for which elements can be added at the front as well as at the rear. It is often called as Head-Tailed Linked List"<cout<<"\t========================"<cout<<"\t\tDequeue Menu"<cout<<"\t========================"<cout<<"[1] Dequeue Of Integer Values"<cout<<"[2] Dequeue Of Floating Values"<cout<<"[3] Dequeue Of Characters"<cout<<"[4] Exit"<cout<<"\t Enter Your Choice"<cin>>choice;
switch(choice)
{
case 1:
clrscr();
int chi;
do
{
cout<<"\t======================="<cout<<"\tDequeue Of Integer Values"<cout<<"\t======================="<cout<<"[1] Insert Element At Front"<cout<<"[2] Insert Element At Rear"<cout<<"[3] Delete Element At Front"<cout<<"[4] Delete Element At Rear "<cout<<"[5] Display Element(s) At Front"<cout<<"[6] Display Element(s) At Rear"<cout<<"[7] Back To Main Menu"<cout<<"\tEnter Your Choice"<cin>>chi;
switch(chi)
{
case 1: dq_int.insfrnt();
break;
case 2: dq_int.insrear();
break;
case 3: dq_int.delfrnt();
break;
case 4: dq_int.delrear();
break;
case 5: dq_int.disfrnt();
break;
case 6: dq_int.disrear();
break;
}
}
while(chi<=6);
break;




case 2:
clrscr();
int chF;
do
{
cout<<"\t======================="<cout<<"\tDequeue Of Floating Values"<cout<<"\t======================="<cout<<"[1] Insert Element At Front"<cout<<"[2] Insert Element At Rear"<cout<<"[3] Delete Element At Front"<cout<<"[4] Delete Element At Rear "<cout<<"[5] Display Element(s) At Front"<cout<<"[6] Display Element(s) At Rear"<cout<<"[7] Back To Main Menu"<cout<<"\tEnter Your Choice"<cin>>chi;
switch(chi)
{
case 1: dq_float.insfrnt();
break;
case 2: dq_float.insrear();
break;
case 3: dq_float.delfrnt();
break;
case 4: dq_float.delrear();
break;
case 5: dq_float.disfrnt();
break;
case 6: dq_float.disrear();
break;
}
}
while(chi<=6);
break;


case 3:
clrscr();
int chc;
do
{
cout<<"\t======================="<cout<<"\tDequeue Of Integer Values"<cout<<"\t======================="<cout<<"[1] Insert Element At Front"<cout<<"[2] Insert Element At Rear"<cout<<"[3] Delete Element At Front"<cout<<"[4] Delete Element At Rear "<cout<<"[5] Display Element(s) At Front"<cout<<"[6] Display Element(s) At Rear"<cout<<"[7] Back To Main Menu"<cout<<"\tEnter Your Choice"<cin>>chc;
switch(chc)
{
case 1: dq_char.insfrnt();
break;
case 2: dq_char.insrear();
break;
case 3: dq_char.delfrnt();
break;
case 4: dq_char.delrear();
break;
case 5: dq_char.disfrnt();
break;
case 6: dq_char.disrear();
break;
}
}
while(chi<=6);
break;





case 4: exit(0);
break;


}
}
while(choice<=3);
}