#include<iostream.h>
#include<conio.h>
#include<process.h>
struct node
{ int info;
node* next;
};
void main()
{
clrscr();
node* front,*rear;
char ch;
do
{
front=rear=NULL;
cout<<"\n";
cout<<"1 to add\n";
cout<<"2 to delete\n";
cout<<"3 to display\n";
cout<<"enter choice";
cin>>ch;
switch(ch)
{
case 1: rear=addQ(front,rear);
if (front==NULL)
front=rear;
break;
case 2: front=delQ(front,rear)
if(front==NULL)
rear=NULL;
break;
case 3: display();
break;
case 4:exit(0);
break;
}
}while(ch<4);
getch();
}
node*addQ(node*front,node*rear)
{
node*ptr;
ptr=new node;
cout<<"enter info:";
cin>>ptr----->info;
ptr------>next=NULL;
if(rear==null)
front=rear=ptr;
else
{ rear------>next=ptr;
rear=ptr;
}
return rear;
}
node *delQ(node*front,node*rear)
{node*ptr;
if(front==NULL)
cout<<"empty!";
else if(front==rear)
{ ptr=front;
front=rear=NULL;
delete ptr;
}
else
{
ptr=front;
front=front----->next;
delete ptr;
}
return front;
}
void display()
{ node*ptr;
if(front==NULL)
cout<<"empty";
else
{ ptr=front;
while(ptr!=NULL)
{ cout<<ptr------->info;
ptr=ptr-------->next;
}
}
}
/* OUTPUT
1 to add
2 to delete
3 to display
enter choice1
enter info13
1 to add
2 to delete
3 to display
enter choice3
13
1 to add
2 to delete
3 to display
enter choice2
1 to add
2 to delete
3 to display
enter choice3
empty
1 to add
2 to delete
3 to display
enter choice4
*/
