Order the queue / storage implementation chain

Queue: linear form having a certain operational constraints, only one end of the insertion, deletion at the other end.

Features: First come, first serve, first-out table

Head front, rear tail

 

Sequential storage

. 1  #define the MaxSize <the maximum number of data elements stored>
 2  
. 3  struct QNode {
 . 4  
. 5  　　the ElementType the Data [the MaxSize];
 . 6  
. 7  　　int REAR;　　// End 
. 8  
. 9  　　int Front;　　// head 
10  
. 11  };
 12 is  
13 is typedef struct * Queue QNode; 
14 // Front REAR = = -1;

 

Circular queue storage approach:

　　(1) use of an additional tag: size or Tag (insert 1, delete 0) domain

　　(2) using only spatial array of n-1

(1) into the queue (circular queue)

 1 void AddQ (Queue PtrQ, ElementType item){
 2 
 3 　　if ( (PtrQ->rear+1) % MaxSize == PtrQ->front ){
 4 
 5 　　　　printf("队列满");
 6 
 7 　　　　return;
 8 
 9 　　}
10 
11 　　PtrQ->reat = (PtrQ->rear+1) % MaxSize;
12 
13 　　PtrQ->Data[PtrQ->rear] = item;
14 
15 }

 

(2) the queue

ElementType DeleteQ ( Queue PtrQ ){

　　if (PtrQ->front == PtrQ->reat) {

　　　　printf("队列空");

　　　　return ERROR;

　　}

　　else {

　　　　PtrQ->front = (PtrQ->front+1) % MaxSize;

　　　　return PtrQ->Data[PtrQ->front];

　　}

}

 

Chain store

struct the Node {// linked list node structure of 

　　the ElementType the Data; 

　　struct the Node * the Next; 

}; 

struct {// chain QNode queue structure 
　　struct Node * rear; // points to the tail node 
　　struct Node * front; // head junction point points }; 
typedef struct QNode * Queue;  Queue PTRQ;

Insert and delete operations are carried out at both ends of the list

 

Without head node chain operations team squad list

The deleteq the ElementType (Queue PTRQ) { 

　　struct the Node * FrontCell; 

　　the ElementType FrotElem; 

　　IF (PtrQ-> Front == NULL) { 

　　　　the printf ( "queue empty" ); 
 　　　　return ERROR; 
 　　} 
 　　FrontCell = PtrQ-> Front; IF (PtrQ-> front == PtrQ-> rear) // If only one queue element  　　　　PtrQ-> front = PtrQ-> rear = NULL; // delete the post queue is empty the else {PtrQ-> = Front PtrQ-> front-> the Next; FrontElem = FrontCell-}> the Data; Free (FrontCell); return FrontElem;}