MOOC 2.3 queue

1. cyclic queue

Sequential storage queue implemented // 
<the maximum number of data elements stored> #define the MaxSize 
struct QNode 
{ 
	the ElementType the Data [the MaxSize]; 
	int REAR; 
	int Front; 
}; 
typedef struct QNode * Queue; 

// 1. enqueue 
void AddQ (PTRQ queue, the ElementType Item) 
{ 
	IF ((PtrQ-> + REAR. 1) ==% PtrQ- the MaxSize> Front) 
	{ 
		the printf ( "queue full"); 
		return; 
	} 
	PtrQ-> REAR = (PtrQ-> + REAR . 1) the MaxSize%; 
	PtrQ-> the Data [PtrQ-> REAR] Item =; 
} 

// 2. dequeue 
the ElementType the deleteq (queue PTRQ) 
{ 
	IF (PtrQ-> == Front PtrQ-> REAR) 
	{ 
		the printf ( "queue empty "); 
		return REEOR; 
	} 
	the else 
	{
		PtrQ->front = (PtrQ->front + 1) % MaxSize;
		return PtrQ->Data[PtrQ->front];
	}
} 

　　

2. Chain queue

// linked storage queue 
struct the Node 
{ 
	the ElementType the Data; 
	struct the Next the Node *; 
}; 
struct QNode 
{ 
	struct the Node * REAR; 
	struct the Node * Front; 
}; 
typedef struct QNode * Queue; 
Queue PTRQ; 

the ElementType the deleteq (Queue PTRQ) 
{ 
	struct the Node * FrontCell; 
	the ElementType FrontElem; 
	
	IF (PtrQ-> Front == NULL) 
	{ 
		the printf ( "queue empty"); 
		return ERROR; 
	} 
	FrontCell = PtrQ-> Front; 
	IF (PtrQ-> == Front PtrQ- > rear) // only one queue element 
	{ 
		PtrQ-> = Front PtrQ-> rEAR = NULL; // delete the queue is empty 
	} 
	the else  
	{
		PtrQ-> = Front PtrQ-> front-> the Next;
	}
	FrontElem = FrontCell->Data;
	free(FrontCell);	// 释放被删除的结点空间 
	return FrontElem;
}

void AddQ(Queue PtrQ, ElementType item)
{
	struct Node node;
	node = (struct Node *)malloc(sizeof(struct Node));
	node->Data = item;
	node->Next = PtrQ->front->Next;
	PtrQ->front->Next = node;
}