Queue implementation in C Language

A queue is a data structure opposite to a stack. It is a first in, first out (FIFO) structure. It is also a structure with limited operations.

ABSTRACT Data Type of the queue:

ADT queue =

{

Initqueue (& Q)

// Create a queue

Destroyqueue (& Q)

// Destroy a queue

Clearqueue (& Q)

// Clear the queue

............

}

Queue implementation in C Language

1:

Ordered queue:

/*************************************** ****
* Filename: squeue. c
* Author: hufeng Date: 2007/11/21
* Version: V1.0
* Description: The program creat a queue and lots
* Of Operating
**************************************** ***/

/* Header file */
# Include <stdio. h>
# Define max 20

/* Creat a struct */
Typedef struct squeue
{
Int date [Max];/* declartion A array */
Int front, rear;/* declarion a front and a rear pointer */

} Sq;

/* Assign queue each ELEM */
Void assign_squeue (SQ * P, int count)
{
Int I;/* declaration a cycle variable */

If (p-> rear> MAX-1)
{
Printf ("overflow! /N ");
Return;
}

Printf ("Please enter each ELEM:/N ");
For (I = 0; I <count; I ++)
{
Scanf ("% d", & P-> date [++ p-> rear]);
}
}

/* Insert a new ELEM in the queue */
Void insert_squeue (SQ * P, int num)
{
If (p-> rear> MAX-1)
{
Printf ("over flow! /N ");
Return;
}

Else
{
P-> date [++ p-> rear] = num;
}

}

/* Delete a elem */
Void delete_squeue (SQ * P)
{
Int X;
If (p-> front = p-> rear)
{
Printf ("Empty queue! /N ");
Return;
}
Else
{
X = p-> date [++ p-> front];
Printf ("p-> front = % d/N", p-> front );
Printf ("the deleted number is: % d/N", X );
}
}

/* Main Program */
Int main ()
{
Sq * P = NULL;/* declaration a pointer */
Int num;/* decalration a number of queue */

P-> front =-1;
P-> rear = p-> front;

Printf ("Please enter the length of queue:/N ");
Scanf ("% d", & num );

Assign_squeue (p, num);/* assign array date */

/* Insert a number in the queue */
Printf ("Please enter which number you want to insert:/N ");
Scanf ("% d", & num );
Insert_squeue (p, num );

/* Delete a number */
Delete_squeue (P );

Getch ();
Return 0;

}

2:

Cyclic queue:

/*************************************** ****
* Filename: cycle_queue.c
* Author: hufeng Date: 2007/11/21
* Version: V1.0
* Description: The program is a cycle queue
**************************************** *****/

/* Header file */
# Include <stdio. h>
# Define max 20

/* Creat a struct */
Typedef struct cycle_queue
{
Int date [Max];
Int front, rear;
} CQ;

/* Assign queue */
Void assign_cyclequeue (CQ * P, int N)
{
Int I;
Int X;

If (n <1 | n> MAX-1)
{
Printf ("overflow! /N ");
Return;
}

Printf ("Please enter each ELEM:/N ");
For (I = 0; I <n; I ++)
{
Scanf ("% d", & X );
P-> date [p-> rear ++] = X;
}
}

/* Insert a number */
Void insert_cyclequeue (CQ * P, int num)
{
If (P-> rear + 1) % max = p-> front)
{
Printf ("Full queue! /N ");
Return;
}
Else
{
P-> date [++ p-> rear] = num;
}
}

/* Delete Number */
Void delete_cyclequeue (CQ * P)
{
Int X;
If (P-> front + 1) % max = p-> rear)
{
Printf ("Empty queue! /N ");
Return;
}

X = p-> date [p-> front];
Printf ("p-> front = % d/N", p-> front );
Printf ("the deleted number is: % d/N", X );
}

/* Main Program */
Int main ()
{

Int num;
CQ * P = NULL;
P-> front = 0;
P-> rear = p-> front;

Printf ("Please enter the length of queue:/N ");
Scanf ("% d", & num );

Assign_cyclequeue (p, num );

Printf ("Please enter the inserting number:/N ");
Scanf ("% d", & num );

Insert_cyclequeue (p, num );
Delete_cyclequeue (P );

Getch ();
Return 0;
}

3.

Chain Team:

/*************************************** ****
* Filename: cycle_queue.c
* Author: hufeng Date: 2007/11/21
* Version: V1.0
* Description: The program is a cycle queue
**************************************** *****/

/* Header file */
# Include <stdio. h>
# Define max 20

/* Creat a struct */
Typedef struct cycle_queue
{
Int date [Max];
Int front, rear;
} CQ;

/* Assign queue */
Void assign_cyclequeue (CQ * P, int N)
{
Int I;
Int X;

If (n <1 | n> MAX-1)
{
Printf ("overflow! /N ");
Return;
}

Printf ("Please enter each ELEM:/N ");
For (I = 0; I <n; I ++)
{
Scanf ("% d", & X );
P-> date [p-> rear ++] = X;
}
}

/* Insert a number */
Void insert_cyclequeue (CQ * P, int num)
{
If (P-> rear + 1) % max = p-> front)
{
Printf ("Full queue! /N ");
Return;
}
Else
{
P-> date [++ p-> rear] = num;
}
}

/* Delete Number */
Void delete_cyclequeue (CQ * P)
{
Int X;
If (P-> front + 1) % max = p-> rear)
{
Printf ("Empty queue! /N ");
Return;
}

X = p-> date [p-> front];
Printf ("p-> front = % d/N", p-> front );
Printf ("the deleted number is: % d/N", X );
}

/* Main Program */
Int main ()
{

Int num;
CQ * P = NULL;
P-> front = 0;
P-> rear = p-> front;

Printf ("Please enter the length of queue:/N ");
Scanf ("% d", & num );

Assign_cyclequeue (p, num );

Printf ("Please enter the inserting number:/N ");
Scanf ("% d", & num );

Insert_cyclequeue (p, num );
Delete_cyclequeue (P );

Getch ();
Return 0;
}