习题3.25 链表和数组对队列例程实现

//循环数组
#define MaxSize 100
struct Queue;
typedef struct Queue * PtrToQ;

struct Queue{
ElementType *Array;
int front;
int rear;
};

PtrToQ
CreateQ( int Size )
{
PtrToQ Q;
Q = malloc( sizeof( struct Queue ) );
Q->Array = malloc( sizeof( ElementType ) * Size );
Q->front = Q->rear = 0;
return Q;
}

int
IsFull( PtrToQ Q )
{
return ( Q->rear + 1 ) % MaxSize == Q->front;
}

void
AddQ( ElementType X, PtrToQ Q )
{
if( !IsFull( Q ) ){
Q->rear = ( Q->rear + 1 ) % MaxSize;
Q->Array[ Q->rear ] = X;
}
else
Error("full")
}

int
IsEmpty( PtrToQ Q )
{
return Q->rear == Q->front;
}

ElementType
DeleteQ( PtrToQ Q )
{
if( !IsEmpty( Q ) )
{
Q->front = ( Q->front + 1 ) % MaxSize;
return Q->front->ele;
}
else
Error();
}