Re: Print Method for Queue List

[Shiro786]

**EDIT**: I figured it out, you can delete this post. I'm leaving it just in case someone else needs help.


I'm trying to figure out how to print a list of Queues. For some reason whenever I try using ' -> ' it says that I'm using an invalid argument. The code is a bit weird; you have to compile an executable before you can run the program itself. My code is at the bottom.

QueueImplementation.c :

code:

#include <stdio.h>                   /* the "QueueTypes.h" file, */ #include <stdlib.h>                  /* given above on lines 1:15, is */ #include "QueueInterface.h"     /* included in "QueueInterface.h" */                                               /* on line 3 of Program 7.4. */    void SystemError(char *errorMsg) {fprintf(stderr,errorMsg);}    void InitializeQueue(Queue *Q)    {       Q->Front = NULL;       Q->Rear  = NULL;    }    int Empty(Queue *Q)    {       return (Q->Front == NULL);    }    int Full(Queue *Q)       {                     /* we assume an already constructed queue, Q, is */       return 0;              /* not full, since it could potentially grow */    }                                             /* as a linked structure */    int Insert(ItemType R, Queue *Q)    {          QueueNode *Temp;                                                    /* attempt to allocate */       Temp = (QueueNode *) malloc(sizeof(QueueNode));       /* a new node */       if (Temp == NULL) {               /* Temp = NULL signals allocation */          SystemError("system storage is exhausted");           /* failure */          return 0;       } else {          Temp->Item = R;          Temp->Link = NULL;          if ( Q->Rear == NULL ) {             Q->Front = Temp;             Q->Rear = Temp;          } else {             Q->Rear->Link = Temp;             Q->Rear = Temp;          }       }       return 1;    }    int Remove(Queue *Q, ItemType *F)    {          QueueNode *Temp;       if (Q->Front == NULL) {          SystemError("attempt to remove item from empty Queue");          return 0 ;       } else {          *F = Q->Front->Item;          Temp = Q->Front;          Q->Front = Temp->Link;          free(Temp);          if (Q->Front == NULL) Q->Rear = NULL;          return 1;       }    }

My Code:

QueueInterface.h :

code:

#include "QueueTypes.h"        /* imports the data type definitions of */                                                     /* ItemType and Queue */ /* defined operations */    extern void InitializeQueue(Queue *Q);       /* Initialize the queue Q to be the empty queue */    extern int Empty(Queue *Q);       /* Returns TRUE == 1 if and only if the queue Q is empty */    extern int Full(Queue *Q);       /* Returns TRUE == 1 if and only if the queue Q is full */    extern int Insert(ItemType R, Queue *Q);       /* If Q is not full, insert a new item R onto the rear of Q */    extern int Remove(Queue *Q, ItemType *F);       /* If Q is non-empty, remove the frontmost item of Q and put it in F */

QueueTypes.c :

code:

typedef  int  ItemType;           /* the ItemType can be arbitrary. */ typedef  struct  QueueNodeTag {             ItemType               Item;                struct  QueueNodeTag  *Link;          }QueueNode;                       typedef  struct {                                 /* a queue is empty iff */             QueueNode  *Front;                       /* its Front == NULL */             QueueNode  *Rear;          }Queue;

QueueDriver.c :

code:

#include <stdio.h> #include <stdlib.h> #include "QueueInterface.h"           int main(void)     {                  Queue Q;           InitializeQueue(&Q);                     if (Empty(&Q) == 1)         {           printf("Queue is empty\n");         }          int number = 1;          while (number <= 7)         {                 Insert(number, &Q);                 if (Empty(&Q) != 1)                 {                   printf("Queue is not empty\n");                 }                 number++;         } }

[md]

If you figured it out then post the solution too. There's nothing worse then when someone says "never mind I figured it out" without posting what they did. Makes finding the solution infinitely more painful.