Circular Queue Using an Array
#include
<stdio.h>
#include<stdlib.h>
#define
MAX 3
char
cq[MAX];
int front = -1,rear = -1;
void
add(char);
void
del();
void
display();
int
main()
{
int
ch;
char
item;
while(1)
{
printf("\n\n~~Main
Menu~~");
printf("\n==> 1.
Insertion and Overflow Demo");
printf("\n==>
2. Deletion and Underflow Demo");
printf("\n==>
3. Display");
printf("\n==>
4. Exit");
printf("\nEnter
Your Choice: ");
scanf("%d",
&ch);
switch(ch)
{
case
1: printf("\n\nEnter the element to be inserted: ");
scanf("%d", &item);
add(item);
break;
case 2: del();
break;
case 3: display();
break;
case
4: exit(0);
default:
printf("\n\nPlease enter a valid choice");
}
}
}
void
add(char item)
{
if(front == (rear+1)%MAX)
printf("\n\n~~Circular
Queue Overflow~~");
else
{
if(front
== -1)
front
= rear = 0;
else
rear
= (rear+1)%MAX;
cq[rear]
= item;
}
}
void
del()
{
char
item;
if(front
== -1)
{
printf("\n\n~~Circular
Queue Underflow~~");
}
else
{
item
= cq[front];
if(front
== rear) //only one element
front
= rear = -1;
else
front
= (front+1)%MAX;
printf("\n\nDeleted
element from the queue is: %d ", item );
}
}
void
display ()
{
int
i ;
if(front
== -1)
{
printf("\n\nCircular
Queue Empty");
return;
}
else
{
printf("\nCircular
Queue contents are:\n");
printf("\nFront[%d]->
", front);
for(i=front;
i!=rear ; i=(i+1)%MAX)
{
printf("
%d", cq[i]);
}
printf(" %d",cq[i]);
printf("
<-[%d]Rear", rear);
}
}
Output:
~~Main
Menu~~
==>
1. Insertion and Overflow Demo
==>
2. Deletion and Underflow Demo
==>
3. Display
==>
4. Exit
Enter
Your Choice: 1
Enter the element to be inserted:
11
~~Main
Menu~~
==>
1. Insertion and Overflow Demo
==>
2. Deletion and Underflow Demo
==>
3. Display
==>
4. Exit
Enter
Your Choice: 1
Enter the element to be inserted:
22
~~Main
Menu~~
==>
1. Insertion and Overflow Demo
==>
2. Deletion and Underflow Demo
==>
3. Display
==>
4. Exit
Enter
Your Choice: 1
Enter the element to be inserted:
33
~~Main
Menu~~
==>
1. Insertion and Overflow Demo
==>
2. Deletion and Underflow Demo
==>
3. Display
==>
4. Exit
Enter
Your Choice: 1
Enter the element to be inserted:
44
~~Circular Queue Overflow~~
~~Main
Menu~~
==>
1. Insertion and Overflow Demo
==>
2. Deletion and Underflow Demo
==>
3. Display
==>
4. Exit
Enter
Your Choice: 3
Circular Queue contents are:
Front[0]-> 11
22 33 <-[2]Rear
~~Main
Menu~~
==>
1. Insertion and Overflow Demo
==>
2. Deletion and Underflow Demo
==>
3. Display
==>
4. Exit
Enter
Your Choice: 2
Deleted element from the queue is:
11
~~Main
Menu~~
==>
1. Insertion and Overflow Demo
==>
2. Deletion and Underflow Demo
==>
3. Display
==>
4. Exit
Enter
Your Choice: 2
Deleted element from the queue is:
22
~~Main
Menu~~
==>
1. Insertion and Overflow Demo
==>
2. Deletion and Underflow Demo
==>
3. Display
==>
4. Exit
Enter
Your Choice: 3
Circular Queue contents are:
Front[2]-> 33 <-[2]Rear
~~Main
Menu~~
==>
1. Insertion and Overflow Demo
==>
2. Deletion and Underflow Demo
==>
3. Display
==>
4. Exit
Enter
Your Choice: 1
Enter the element to be inserted:
66
~~Main
Menu~~
==>
1. Insertion and Overflow Demo
==>
2. Deletion and Underflow Demo
==>
3. Display
==>
4. Exit
Enter
Your Choice: 3
Circular Queue contents are:
Front[2]->
33 66 <-[0]Rear
