C++ program to implement circular queue using array
#include <iostream.h>
class cqueue
{
private :
int *arr ;
int front, rear ;
int MAX;
public :
cqueue( int maxsize = 10 ) ;
void addq ( int item ) ;
int delq( ) ;
void display( ) ;
} ;
cqueue :: cqueue( int maxsize )
{
MAX = maxsize ;
arr = new int [ MAX ];
front = rear = -1 ;
for ( int i = 0 ; i < MAX ; i++ )
arr[i] = 0 ;
}
void cqueue :: addq ( int item )
{
if ( ( rear + 1 ) % MAX == front )
{
cout << "\nQueue is full" ;
return ;
}
rear = ( rear + 1 ) % MAX;
arr[rear] = item ;
if ( front == -1 )
front = 0 ;
}
int cqueue :: delq( )
{
int data ;
if ( front == -1 )
{
cout << "\nQueue is empty" ;
return NULL ;
}
data = arr[front] ;
arr[front] = 0 ;
if ( front == rear )
{
front = -1 ;
rear = -1 ;
}
else
front = ( front + 1 ) % MAX;
return data ;
}
void cqueue :: display( )
{
cout << endl ;
for ( int i = 0 ; i < MAX ; i++ )
cout << arr[i] << " " ;
cout << endl ;
}
void main( )
{
cqueue a ( 10 ) ;
a.addq ( 14 ) ;
a.addq ( 22 ) ;
a.addq ( 13 ) ;
a.addq ( -6 ) ;
a.addq ( 25 ) ;
cout << "\nElements in the circular queue: " ;
a.display( ) ;
int i = a.delq( ) ;
cout << "Item deleted: " << i ;
i = a.delq( ) ;
cout << "\nItem deleted: " << i ;
cout << "\nElements in the circular queue after deletion: " ;
a.display( ) ;
a.addq ( 21 ) ;
a.addq ( 17 ) ;
a.addq ( 18 ) ;
a.addq ( 9 ) ;
a.addq ( 20 ) ;
cout << "Elements in the circular queue after addition: " ;
a.display( ) ;
a.addq ( 32 ) ;
cout << "Elements in the circular queue after addition: " ;
a.display( ) ;
} |
there is no ‘queue is full’ concept in circular buffer. you need to modify ur code to rollover the rear piinter.
in above comment i read that there is no concept of Full… but i run it There is concept of IS FULL… just type Int in place of void and run it,,,
@ Dummy….Not necessary pal…There are many ways to look at it..
If you ask me I will write 3 methods or one method with three modes
– Enqueue Soft – Just tries to add element, fails if the queue is full
– Enqueue Hard – Somehow adds the element by allocating extra memory
– Enqueue Forced – This is what you are talking about, It simply adds the element by dropping the first element(dequeued)
bro tell me about circular queue in easiest code .
@ Author…Why don’t you templatize this program so that it can take any type of elements?
mail id
[email protected]
send me all conceptual data about this topic
this code is wrong it doesn’t move the item inside it
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/*
* C++ Program to Implement Circular Queue
*/
#include
#define MAX 5
using namespace std;
/*
* Class Circular Queue
*/
class Circular_Queue
{
private:
int *cqueue_arr;
int front, rear;
public:
Circular_Queue()
{
cqueue_arr = new int [MAX];
rear = front = -1;
}
/*
* Insert into Circular Queue
*/
void insert(int item)
{
if ((front == 0 && rear == MAX-1) || (front == rear+1))
{
cout<<"Queue Overflow \n";
return;
}
if (front == -1)
{
front = 0;
rear = 0;
}
else
{
if (rear == MAX – 1)
rear = 0;
else
rear = rear + 1;
}
cqueue_arr[rear] = item ;
}
/*
* Delete from Circular Queue
*/
void del()
{
if (front == -1)
{
cout<<"Queue Underflow\n";
return ;
}
cout<<"Element deleted from queue is : "<<cqueue_arr[front]<<endl;
if (front == rear)
{
front = -1;
rear = -1;
}
else
{
if (front == MAX – 1)
front = 0;
else
front = front + 1;
}
}
/*
* Display Circular Queue
*/
void display()
{
int front_pos = front, rear_pos = rear;
if (front == -1)
{
cout<<"Queue is empty\n";
return;
}
cout<<"Queue elements :\n";
if (front_pos <= rear_pos)
{
while (front_pos <= rear_pos)
{
cout<<cqueue_arr[front_pos]<<" ";
front_pos++;
}
}
else
{
while (front_pos <= MAX – 1)
{
cout<<cqueue_arr[front_pos]<<" ";
front_pos++;
}
front_pos = 0;
while (front_pos <= rear_pos)
{
cout<<cqueue_arr[front_pos]<<" ";
front_pos++;
}
}
cout<<endl;
}
};
/*
* Main
*/
int main()
{
int choice, item;
Circular_Queue cq;
do
{
cout<<"1.Insert\n";
cout<<"2.Delete\n";
cout<<"3.Display\n";
cout<<"4.Quit\n";
cout<>choice;
switch(choice)
{
case 1:
cout<>item;
cq.insert(item);
break;
case 2:
cq.del();
break;
case 3:
cq.display();
break;
case 4:
break;
default:
cout<<"Wrong choice\n";
}/*End of switch*/
}
while(choice != 4);
return 0;
}
I Hope , This Code will Help you!!!
the above code is correct 100%. just one mistake there , in void main( ). type int main () . then program will run correctly.. i run it .. it works with all operation like is Full , is Empty , Dequeue and enqueue etc.. it works all .. in c-Free or Dev
in above comment i read that there is no concept of Full… but i run it There is concept of IS FULL… just type Int in place of void and run it,,,
I would not trust this code.
It does not do what it claims: it is not a circular queue. A circular queue never gets “full,” it’s like a circle: it just keeps going around.
Also, since we’re putting the data on the heap with the following statement:
arr = new int [ MAX ];
and it has no destructor, there is probably a memory leak.
There’s probably more problems, but I look no further. The above is enough to lose my trust in this code.
i need array implementation queue program for following functions as arrayqueue(),enqueue(),dequeue(),front(),
back().