struct Node;struct QueueRecord;typedef struct Node * PtrToNode;typedef struct QueueRecord * Queue;struct Node{    ElementType Element;    PtrToNode Next;};struct QueueRecord{    PtrToNode Front;    PtrToNode Rear;};Queue CreateQueue( );void DisposeQueue( Queue Q );int IsEmpty( Queue Q );void MakeEmpty( Queue Q );void Enqueue( ElementType X, Queue Q );void Dequeue( Queue Q );ElementType Front( Queue Q );ElementType FrontAndDequeue( Queue Q );Queue CreateQueue(){    Queue Q;    Q = (Queue) malloc( sizeof( struct QueueRecord ) );    if ( NULL == Q )    {        printf( "Out of Space!!!" );        return NULL;    }    // 链表栈中含有头结点    Q->Front = Q->Rear = ( PtrToNode ) malloc( sizeof( struct QueueRecord ) );    if ( Q->Front == NULL )    {        printf( "Out of space!!!" );        return NULL;    }    Q->Front->Next = NULL;    return Q;}void DisposeQueue( Queue Q ){    while( !IsEmpty(Q) )        Dequeue( Q );    free( Q->Front );    free( Q );}void Enqueue( ElementType X, Queue Q ){    PtrToNode TmpCell;    TmpCell = (PtrToNode) malloc( sizeof( struct Node ) );    if ( TmpCell == NULL )    {        printf("Out of space!!!");        return;    }    else    {        TmpCell->Element = X;        TmpCell->Next = NULL;        Q->Rear->Next = TmpCell;        Q->Rear = TmpCell;    }}void Dequeue( Queue Q ){    if ( IsEmpty(Q) )    {        printf( "Out of space!!!" );        return;    }    else    {        PtrToNode TmpCell;        TmpCell = Q->Front->Next;        Q->Front->Next = TmpCell->Next;        if ( Q->Rear == TmpCell )            Q->Rear = Q->Front;        free( TmpCell );    }}int IsEmpty( Queue Q ){    return Q->Front->Next == NULL;}void MakeEmpty( Queue Q ){    if ( Q == NULL )    {        printf( "Must creat queue first!" );        return;    }        while ( !IsEmpty(Q) )        Dequeue( Q );}ElementType Front( Queue Q ){    if ( IsEmpty(Q) )    {        printf( "Empty Queue" );        return 0;    }    else        return Q->Front->Next->Element;}ElementType FrontAndDequeue( Queue Q ){    ElementType TmpCell;    if ( IsEmpty(Q) )    {        printf( "Empty Queue" );        return 0;            }    else    {        TmpCell = Front( Q );        Dequeue( Q );        return TmpCell;    }}