数据结构-队列与双端队列(C描述)
2010-05-06 11:59:03 来源:WEB开发网queue.c
#include "queue.h"
#include "fatal.h"
#define MinQueueSize 5
struct QueueRecord
{
int Capacity;
int Front;//指向队头元素
int Rear;//指向队尾元素
int Size;
ElementType *Array;
};
int IsEmpty(Queue Q)
{
return Q->Size == 0;
}
int IsFull(Queue Q)
{
return Q->Size == Q->Capacity;
}
Queue CreateQueue(int MaxElements)
{
Queue Q;
if(MaxElements < MinQueueSize)
Error("Queue size is too small");
Q = malloc(sizeof(struct QueueRecord));
if(Q == NULL)
FatalError("Out of space!!!");
Q->Array = malloc(sizeof(ElementType) * MaxElements);
if(Q->Array == NULL)
FatalError( "Out of space!!!" );
Q->Capacity = MaxElements;
MakeEmpty(Q);
return Q;
}
void MakeEmpty(Queue Q)
{
Q->Size = 0;
Q->Front = 1;
Q->Rear = 0;
}
void DisposeQueue(Queue Q)
{
if(Q != NULL)
{
free(Q->Array);
free(Q);
}
}
static int Succ(int Value, Queue Q)
{
if(++Value == Q->Capacity)
Value = 0;
return Value;
}
void Enqueue(ElementType X, Queue Q)
{
if(IsFull(Q))
Error("Full queue");
else
{
Q->Size++;
Q->Rear = Succ(Q->Rear, Q);
Q->Array[Q->Rear] = X;
}
}
ElementType Front(Queue Q)
{
if(!IsEmpty(Q))
return Q->Array[Q->Front];
Error("Empty queue");
return 0; /* Return value used to avoid warning */
}
void Dequeue(Queue Q)
{
if(IsEmpty(Q))
Error( "Empty queue" );
else
{
Q->Size--;
Q->Front = Succ(Q->Front, Q);
}
}
ElementType FrontAndDequeue(Queue Q)
{
ElementType X = 0;
if(IsEmpty(Q))
Error("Empty queue");
else
{
Q->Size--;
X = Q->Array[Q->Front];
Q->Front = Succ(Q->Front, Q);
}
return X;
}
更多精彩
赞助商链接