Any help is greatly appreciated..
How do I read this information int a Doubly Linked List? I don't
even know where to start.
Code:#include<iomanip.h> #include<string> #include<fstream> #include"DubDV_listP.C" ifstream IF ("csc23565_lab4.txt"); ofstream OF ("OUTPUT_lab4.txt"); typedef struct{ string lastName; string phoneNumber; string course[15]; } Person; main() { int RecCount=1; Person Rec; if( !IF ) {cout<<"cannot open file"<<endl; exit;} // loop for Records of Person while ( IF >> Rec.lastName) { OF<<Rec.lastName << " "; cout <<" "; cout <<Rec.lastName<<" "; IF >>Rec.phoneNumber; OF<<Rec.phoneNumber << " "; cout <<Rec.phoneNumber<<" "; // loop through the courses for this Record int courseIndex=0; // reseting the array index to zero IF >>Rec.course[courseIndex]; while (Rec.course[courseIndex] != "XXX111") {cout<<Rec.course[courseIndex]<<" "; OF<<Rec.course[courseIndex]; courseIndex++; IF>>Rec.course[courseIndex]; }// end of course loop OF << endl; cout << endl; RecCount++; c++; }// end of while loop for records of Person }
The sample info in the txt file is basically a directory of students:
Arthur 1234567890 MTH235 PHY235 SOC235 XXX111
Grant 1234567890 PSY235 ART235 XX111
Johns 1234567890 CSC235 XXX111
and the file "DubDV_listP.C" I'm including is :
Code:typedef int DlistItemType; class DlistNode; // linked list node typedef DlistNode* ptrType; // pointer to node class DlistNode // a node on the list { friend class DlistClass; DlistItemType DItem; // a data item on the list ptrType DNext; // pointer to next node ptrType DPrev; // pointer to prev node }; // end class listNode class DlistClass { public: // constructors and destructor: DlistClass(); // default constructor DlistClass(const DlistClass& L); // copy constructor ~DlistClass(); // destructor // list operations: bool DListIsEmpty() const; int DListLength() const; void DListInsert(int NewPosition, DlistItemType NewItem, bool& Success); void DListDelete(int Position, bool& Success); void DListRetrieve(int Position, DlistItemType& DataItem, bool& Success) const; private: int Size; // number of items in list ptrType Head; // pointer to linked list of items ptrType Tail; ptrType DPtrTo(int Position) const; // Returns a pointer to the Position-th node // in the linked list. }; // end class DlistClass::DlistClass(const DlistClass& L): Size(L.Size) { if (L.Head == NULL) Head = NULL; // original list is empty else { // copy first node Head = new DlistNode; assert(Head != NULL); // check allocation Head->DItem = L.Head->DItem; // copy rest of list ptrType NewPtr = Head; // new list pointer // NewPtr points to last node in new list // OrigPtr points to nodes in original list for (ptrType OrigPtr = L.Head->DNext; OrigPtr != NULL; OrigPtr = OrigPtr->DNext) { NewPtr->DNext = new DlistNode; assert(NewPtr->DNext != NULL); NewPtr = NewPtr->DNext; NewPtr->DItem = OrigPtr->DItem; } // end for NewPtr->DNext = NULL; } // end if } // end copy constructor DlistClass::~DlistClass() { bool Success; while (!DListIsEmpty()) DListDelete(1, Success); } // end destructor bool DlistClass::DListIsEmpty() const { return bool(Size == 0); } // end ListIsEmpty int DlistClass::DListLength() const { return Size; } // end ListLength ptrType DlistClass::DPtrTo(int Position) const // -------------------------------------------------- // Locates a specified node in a linked list. // Precondition: Position is the number of the // desired node. // Postcondition: Returns a pointer to the desired // node. If Position < 1 or Position > the number of // nodes in the list, returns NULL. // -------------------------------------------------- { if ( (Position < 1) || (Position > DListLength()) ) return NULL; else // count from the beginning of the list { ptrType Cur = Head; for (int Skip = 1; Skip < Position; ++Skip) Cur = Cur->DNext; return Cur; } // end if } // end PtrTo void DlistClass::DListRetrieve(int Position, DlistItemType& DataItem, bool& Success) const { Success = bool( (Position >= 1) && (Position <= DListLength()) ); if (Success) { // get pointer to node, then data in node ptrType Cur = DPtrTo(Position); DataItem = Cur->DItem; } // end if } // end ListRetrieve void DlistClass::DListInsert(int NewPosition, DlistItemType NewItem, bool& Success) { int NewLength = DListLength() + 1; Success = bool( (NewPosition >= 1) && (NewPosition <= NewLength) ); if (Success) { // create new node and place NewItem in it ptrType NewPtr = new DlistNode; Success = bool(NewPtr != NULL); if (Success) { Size = NewLength; NewPtr->DItem = NewItem; // attach new node to list if (NewPosition == 1) { // insert new node at beginning of list NewPtr->DNext = Head; Head = NewPtr; } else { ptrType Prev = DPtrTo(NewPosition-1); // insert new node after node // to which Prev points NewPtr->DNext = Prev->DNext; Prev->DNext = NewPtr; } // end if } // end if } // end if } // end ListInsert void DlistClass::DListDelete(int Position, bool& Success) { ptrType Cur; Success = bool( (Position >= 1) && (Position <= DListLength()) ); if (Success) { --Size; if (Position == 1) { // delete the first node from the list Cur = Head; // save pointer to node Head = Head->DNext; } else { ptrType Prev = DPtrTo(Position-1); // delete the node after the // node to which Prev points Cur = Prev->DNext; // save pointer to node Prev->DNext = Cur->DNext; } // end if // return node to system Cur->DNext = NULL; delete Cur; Cur = NULL; } // end if } // end ListDelete // END of listClass Implementation Code
If you've read this far, thank you. I don't normally post this much code, but I just don't know where to start with my problem.. i've been drawing blanks since yesterday.
