Program - Create Double Ended Queue using Array
Algorithm
– Insertion at rear end
Step -1 : [Check for overflow]
if(rear==MAX)
Output
"Queue is Overflow”
return;
Step-2 : [Insert element]
else
rear=rear+1;
q[rear]=no;
[Set
rear and front pointer]
if rear=0
rear=1;
if
front=0
front=1;
Step-3 : return
Algorithm
: Insertion at front end
Step-1 : [Check for the front position]
if(front<=1)
Ourput
“Cannot add value at front end”
return;
Step-2 : [Insert at front]
else
front=front-1;
q[front]=no;
Step-3 : Return
Algorithm
:Deletion from front end
Step-1 [ Check for front pointer]
if front=0
Output " Queue is Underflow”
return;
Step-2 [Perform deletion]
else
no=q[front];
Output
“Deleted element is”,no
[Set front and rear pointer]
if front=rear
front=0;
rear=0;
else
front=front+1;
Step-3 : Return
Algorithm
: deletion from rear end
Step-1 : [Check for the rear
pointer]
if
rear=0
Output “Cannot delete value at rear end”
return;
Step-2: [ perform deletion]
else
no=q[rear];
[Check
for the front and rear pointer]
if
front= rear
front=0;
rear=0;
else
rear=rear-1;
Output “Deleted element is”,no
Step-3 : Return
Program
#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
#define MAX 10
int q[MAX],front=0,rear=0;
void add_rear();
void add_front();
void delete_rear();
void delete_front();
void display();
void main()
{
int
ch;
clrscr();
do
{
//clrscr();
printf("\n
DQueue Menu");
printf("\n--------------");
printf("\n
1. AddRear");
printf("\n
2. AddFront");
printf("\n
3. DeleteRear");
printf("\n
4. DeleteFront");
printf("\n
5. Display");
printf("\n
6. Exit");
printf("\n--------------");
printf("\n
Enter your choice:-");
scanf("%d",&ch);
switch(ch)
{
case
1:
{
add_rear();
printf("\n
Queue after insert at rear");
display();
break;
}
case
2:
{
add_front();
printf("\n Queue after insert at
front");
display();
break;
}
case
3:
{
delete_rear();
printf("\n
Queue after delete at rear");
display();
break;
}
case
4:
{
delete_front();
printf("\n
Queue after delete at front");
display();
break;
}
case
5:
{
display();
break;
}
case
6:
{
exit(0);
break;
}
default:
{
printf("\n
Wrong Choice\n");
}
}
}
while(ch!=6);
}
void add_rear()
{
int
no;
printf("\n
Enter value to insert : ");
scanf("%d",&no);
if(rear==MAX)
{
printf("\n
Queue is Overflow");
return;
}
else
{
rear++;
q[rear]=no;
if(rear==0)
rear=1;
if(front==0)
front=1;
}
}
void add_front()
{
int
no;
printf("\n
Enter value to insert:-");
scanf("%d",&no);
if(front<=1)
{
printf("\n
Cannot add value at front end");
return;
}
else
{
front--;
q[front]=no;
}
}
void delete_front()
{
int
no;
if(front==0)
{
printf("\n
Queue is Underflow\n");
return;
}
else
{
no=q[front];
printf("\n
Deleted element is %d\n",no);
if(front==rear)
{
front=0;
rear=0;
}
else
{
front++;
}
}
}
void delete_rear()
{
int
no;
if(rear==0)
{
printf("\n
Cannot delete value at rear end\n");
return;
}
else
{
no=q[rear];
if(front==rear)
{
front=0;
rear=0;
}
else
{
rear--;
printf("\n
Deleted element is %d\n",no);
}
}
}
void display()
{
int
i;
if(front==0)
{
printf("\n
Queue is Underflow\n");
return;
}
else
{
printf("\n
Output");
for(i=front;i<=rear;i++)
{
printf("\n
%d",q[i]);
}
}
}
Posted By : Ruchita Pandya
