[Algorithm and data structure] _ 9 _ linear structure _ queue _ continued _ 1

A section about queueSource codeYou may find thatCodeSome problems exist. That is, if the frontend points to the end of the queue after leaving the queue;

An exception occurs. Therefore, to be able to use the queue, You need to modify the source code.

 /*  * BookProgramTest linear data structure: queue  */  # Include <Stdio. h> # Include <Stdlib. h> //  ************************************* 0  //  Define data types  Struct  Queuenode { //  If rear =-1 and front =-1, the queue does not exist.  //  The queue does not exist and cannot perform any operations on the queue.      Int * Queue;  Int Front; //  First queue      Int Rear; //  End of queue      Int  Maxsize ;}; typedef  Struct Queuenode queue; typedef queue * Pqueue; typedef  Enum  {False, true} bool;  //  * ************************************ 1  //  ************************************* 0  //  Define User Constants  # Define Max_queue_size 4 //  * ************************************ 1  // ************************************* 0  Pqueue createqueue (  Void  ); Bool initqueue (pqueue Queue); bool isempty (pqueue Queue); bool isfull (pqueue Queue); bool enqueue (pqueue queue,  Int  Element); bool dequeue (pqueue queue,  Int * Element );  Int Main ( Void  ) {Pqueue queue;  Int  X; queue =Createqueue ();  If  (Initqueue (Queue) puts (  "  Yes  "  );  If  (Isempty (Queue) puts (  "  Yes  "  );  If (Enqueue (queue, 1  ) Puts ( "  En success  "  );  If (Enqueue (queue, 1  ) Puts (  "  En success  "  );  If (Enqueue (queue, 1  ) Puts (  "  En success "  );  If (Enqueue (queue, 1  ) Puts (  "  En success  " ); //  In this way, output three ensuccess instances.      If  (Isfull (Queue) puts (  "  Yes  "  ); If (Dequeue (queue ,& X) printf (  "  Dequeue success, % d \ n  "  , X );  If (Enqueue (queue, 1  ) Puts (  "  En success  "  ); Getchar ();  Return   0 ;}  //  * ************************************ 1  //  ************************************* 0  /*  Function: Create a queue function prototype: pqueue createqueue (void) function parameter: no return value: If the creation is successful, the queue storage address is returned; otherwise, an error is returned: None  */  Pqueue createqueue (  Void  ) {Pqueue queue; queue = Malloc ( Sizeof  (Queue ));  If (Queue) {queue -> Front =- 1  ; Queue -> Rear =- 1  ;  Return  Queue ;}  Else  {  Return  NULL ;}}  //  * ************************************ 1  // ************************************* 0  /*  Function: Initialize the queue function prototype: bool initqueue (pqueue Queue) function parameter: pqueue queue: returned value of the queue to be initialized: True is returned if Initialization is successful; otherwise, false is returned. Exception: None  */  Bool initqueue (pqueue Queue ){  If (! Queue)  Return  False; queue -> Queue = malloc ( Sizeof ( Int )* Max_queue_size ); If  (Queue) {queue -> Front =- 1  ; Queue -> Rear = 0  ; Queue -> Maxsize = Max_queue_size;  Return  True ;}  Else  {  Return  False ;}}  // * ************************************ 1  //  ************************************* 0  /*  Function: determines whether the queue is empty. function prototype: bool isempty (pqueue Queue) function parameter: pqueue queue: queue pointer function return value: If it is null, true is returned; otherwise, false is returned: none  */  Bool isempty (pqueue Queue ){  If (! Queue | queue-> rear =- 1  ) {Puts (  "  Error.  " ); Exit (  0  );}  Return Queue-> rear = 0 ? True: false ;}  //  * ************************************ 1  //  ************************************* 0  /*  Function: determines whether the queue is full. function prototype: bool isfull (pqueue Queue) function parameter: pqueue queue: queue pointer function return value: If it is full, true is returned; otherwise, false is returned: none  */ Bool isfull (pqueue Queue ){  If (! Queue | queue-> rear =- 1  ) {Puts (  "  Error.  "  ); Exit (  0  );}  If (- 1 = Queue-> front & queue-> rear = (queue-> maxsize- 1  )) Return  True;  Else          Return  False ;}  //  ************************************* 0  //  ************************************* 0  /*  Function: Move the queue element to-1. function prototype: void movequeue (pqueue) function parameter: pqueue queue: queue return value: no exception: None  */  Void  Movequeue (pqueue Queue ){ Int  I, J;  //  This function is only used in the queue function, and the validity is completed in the queue function. I = queue-> Front; queue -> Front =- 1  ; J = 0  ;  While (J < I) {queue -> Queue [J] = queue-> queue [I + J]; j ++ ;} Queue -> Rear = queue-> maxsize-queue-> Front ;}  //  * ************************************ 1  //  ************************************* 0  /*  Function: queuing function prototype: bool enqueue (pqueue queue, int element) function parameter: pqueue queue: queue int element: Elements to be queued return value: Successful, true is returned; otherwise, false is returned. Exception: None  */  Bool enqueue (pqueue queue,  Int  Element ){  If (! Queue | queue-> rear =-1  ) {Puts (  "  Error.  "  ); Exit (  0  );}  If  (Isfull (Queue ))  Return  False;  Else  {  /* This logic can also be used here to make it simpler if (queue-> rear = queue-> maxsize-1) movequeue (Queue ); queue-> queue [queue-> rear ++] = element; return true;  */          If (Queue-> rear! = Queue-> maxsize- 1  ){  //  If the last rear is not reached, add Queue-> queue [queue-> rear ++] = Element;  Return  True ;}  Else {  //  If the rear reaches the end and the queue is not full, move the element  //  After moving, add the element  Movequeue (Queue); queue -> Queue [queue-> rear ++] = Element;  Return  True ;}}}  //  * ************************************ 1  //  ************************************* 0 /*  Function: out-of-band function prototype: bool dequeue (pqueue queue, int * element) function parameter: pqueue queue: queue int * element: stores the element return value after the out-of-band operation: If the out-of-queue operation is successful, true is returned, and * element = the first element of the team is set. If the team fails, false is returned, and * element = 0 is set. Exception: none.  */  Bool dequeue (pqueue queue,  Int * Element ){  If (! Queue | queue-> rear =- 1  ) {Puts (  "  Error.  " ); Exit (  0  );}  If  (Isempty (Queue ))  Return  False; * Element = queue-> queue [++ queue-> Front];  Return  True ;}  //  ************************************* 0 

The code running result is as follows:

If the cyclic queue is used, the above problems will not exist.