Basic queue operations

Two types of queue storage structures are available: Linear table Storage and chained storage. When using a linear table for storage, note whether the queue length exceeds the preset size. In this program, the queue length can be automatically increased when the queue is full. If you use a linked list for storage, there is no length limit. The following describes the implementation of these two storage structures.

Linear table Storage:

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# Define QUEUE_INIT_SIZE 10 # define QUEUE_REALLOCATION 2 typedef int ElemType;/* Storage Structure Definition of ordered queues */typedef struct SqQueue {ElemType * base; int front; int rear; int QueueLength ;} sqQueue; void Init_SqQueue (SqQueue * S) {S-> base = (ElemType *) malloc (QUEUE_INIT_SIZE * sizeof (ElemType); if (! S-> base) exit (1); S-> rear = S-> front = 0; S-> QueueLength = QUEUE_INIT_SIZE;} void En_SqQueue (SqQueue * S, ElemType e) {if (S-> rear + 1) % S-> QueueLength = S-> front) {S-> base = (ElemType *) malloc (S-> base, (S-> QueueLength + QUEUE_REALLOCATION) * sizeof (ElemType); if (! S-> base) exit (1); if (S-> front> S-> rear) {int I; for (I = S-> front; I <S-> QueueLength; ++ I) {S-> base [I + QUEUE_REALLOCATION] = S-> base [I];} S-> front + = QUEUE_REALLOCATION ;} s-> QueueLength + = QUEUE_REALLOCATION;} S-> base [S-> rear] = e; S-> rear = (S-> rear + 1) % S-> QueueLength;} int De_SqQueue (SqQueue * S, ElemType * e) {if (S-> rear = S-> front) return 0; * e = S-> base [S-> front]; S-> front = (S-> front + 1) % S-> Queue Length; return 1;} int SqQueueLength (SqQueue S) {return (S. rear-S. front + S. queueLength) % S. queueLength;} int is_SqQueueEmpty (SqQueue S) {if (S. front = S. rear) return 1; elsereturn 0;} void SqQueueTest () {SqQueue S; Init_SqQueue (& S); printf ("Please input some numbers to enqueue (Ctrl + Z to end ): \ n "); int e; while (scanf (" % d ", & e )! = EOF) En_SqQueue (& S, e); printf ("The dequeue sequence is: \ n"); while (! Is_SqQueueEmpty (S) {De_SqQueue (& S, & e); printf ("% d", e);} printf ("\ n");} int main () {SqQueueTest (); return 0 ;}
  
 

Linked List storage:

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/* Storage Structure Definition of chain queue */typedef struct LinkQueue_Node {ElemType data; struct LinkQueue_Node * next;} * Queue_pNode, Queue_Node; typedef struct LinkQueue {struct LinkQueue_Node * front; struct LinkQueue_Node * rear;} LinkQueue; void Init_LinkQueue (LinkQueue * L) {L-> front = L-> rear = (Queue_pNode) malloc (sizeof (Queue_Node); if (! L-> front) exit (1); L-> front-> data = 0; L-> front-> next = NULL;} void En_LinkQueue (LinkQueue * L, elemType e) {Queue_pNode p = (Queue_pNode) malloc (sizeof (Queue_Node); if (! P) exit (1); p-> data = e; p-> next = NULL; L-> rear-> next = p; L-> rear = p ;} int De_LinkQueue (LinkQueue * L, ElemType * e) {Queue_pNode p = L-> front-> next; if (L-> front = L-> rear) return 0; * e = p-> data; L-> front-> next = p-> next; if (p = L-> rear) l-> rear = L-> front; free (p); return 1;} int LinkQueueLength (LinkQueue L) {Queue_pNode p = L. front; if (L. front = L. rear) return 0; int length = 0; while (p! = L. rear) {++ length; p = p-> next;} return length;} int is_LinkQueueEmpty (LinkQueue L) {if (L. front = L. rear) return 1; elsereturn 0;} void LinkQueueTest () {LinkQueue L; Init_LinkQueue (& L); printf ("Please input some numbers to enqueue (Ctrl + Z to end ). \ n "); int e; while (scanf (" % d ", & e )! = EOF) En_LinkQueue (& L, e); printf ("The dequeue sequence is: \ n"); while (! Is_LinkQueueEmpty (L) {De_LinkQueue (& L, & e); printf ("% d", e);} printf ("\ n");} int main () {LinkQueueTest (); return 0 ;}