Quick LinkList Help!!adding at the End

This is a discussion on Quick LinkList Help!!adding at the End within the C++ Programming forums, part of the General Programming Boards category; Hi everyone, I am having a little problem figuring out how to add element at the end of the LinkList. ...

  1. #1
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    Question Quick LinkList Help!!adding at the End

    Hi everyone,

    I am having a little problem figuring out how to add element at the end of the LinkList. Here is my program that adds element at front of the Linklist. The Function that add the Element to the front is addStudent() in Student class. Can any one fix these for me.....

    Thanks
    Code:
    #include<iostream.h>
    #include<cstring>
    #include<cstdlib>
    #include<fstream.h>
    #include <iomanip>
    
    #define Channel 200
    #define Y true
    #define N false
    #define True 0		/* Allies for Zero*/
    #define False 1		/* Allies for ONE*/
    
    class Student;
    class Person{
            protected:
                    char *Name;
                    char *ID;
                    char *Email;
                    char *Phone;
            public:        
            	Person();
            	~Person();
    };
    
    class Student : public Person{
            private:
                    char *Major;
                    Student *next;
            public:
             	Student();
             	
             	void setName(char *);
    		void setID(char *);
    		void setPhone(char *);
    		void setEmail(char *);
    		void setMajor(char *);
    		void setNext(Student *);
    
    
    		char* getName()const{return Name;}
    		char* getID()const{return ID;}
    		char* getPhone()const{return Phone;}
    		char* getEmail()const{return Email;}
    		char* getMajor()const{return Major;}
    		Student *getNext()const{return next;}
             	
             	void addStudent (char *,char *,char *,char *,char *,Student *&);
             	~Student();
    };
    
    /*Opening all the file to run an make linklist after file processing*/
    void funOpenFile(Student *&);
    
    /*functions used for processing Student.dat file, and make a linklist*/
    void StudentGetData (fstream &,Student *&);
    void Sdatastore(int ,char *,Student *&);
    void showStudent(Student *);
    
    Person::Person()
    {
    	Name = new char[30];
    	ID = new char[10];
    	Email = new char[30];
    	Phone = new char[15];
    }
    
    Person::~Person()
    {
    	delete[] Name;
    	delete[] ID;
    	delete[] Email;
    	delete[] Phone;
    }
    
    Student::Student():Person()
    {
    	Major = new char[30];
    	next = NULL;
    }
    
    Student::~Student()
    {
    	delete[] Major;
    }
    
    int main()
    {
      Student *ptrStartStud = NULL;
           
           funOpenFile(ptrStartStud);
           showStudent(ptrStartStud);//Enable to check nothing is wrong while loading the LinkList 	
     
      return 0;
    }
    
    void funOpenFile (Student *&rootStudent)
    {
    	fstream StudentFileInPtr;
    	
    	StudentFileInPtr.open("Student.dat",ios::in);
    	
    	if(StudentFileInPtr.fail())
    	{
    		cerr<<"Error Opening The File"<<endl;
    	}
    	else
    	{
    		StudentGetData (StudentFileInPtr,rootStudent);	
    	}
    }
    
    void StudentGetData (fstream &ReadFileInPtr,Student *&topStudent)
    {
    	char *chtokenPtr,szPharseFile[Channel];
    	int ncounter = 0;
    
    	while(!(ReadFileInPtr.getline(szPharseFile,200,'\n')).eof())
    	{			
    		chtokenPtr = strtok(szPharseFile,"\t");
    		while(chtokenPtr != NULL)
    		{
    			ncounter++;
    			if(ncounter == 6 )
    			{
    				ncounter = 1;
    			}
    			Sdatastore(ncounter,chtokenPtr,topStudent);
    			chtokenPtr = strtok(NULL,"\t\n");				
    			}			
    		}
    }
    
    void Sdatastore(int ncounter,char *prtokenPtr,Student *&topStudent)
    {
            static char szName[30],szID[9],szEmail[30],szPhone[13],szMajor[30];
    	enum Status{stage1 = 1,stage2,stage3,stage4,stage5};
    	Student NewPtrI;
    		switch(ncounter)
    		{
    		case stage1:
    			{
    			strcpy(szName,prtokenPtr);
    			break;
    			}
    		case stage2:
    			{
    			strcpy(szID,prtokenPtr);
    			break;
    			}
    		case stage3:
    			{
    			strcpy(szEmail,prtokenPtr);
    			break;
    			}
    		case stage4:
    			{
    			strcpy(szPhone,prtokenPtr);
    			break;
    			}
    		case stage5:
    			{
    				strcpy(szMajor,prtokenPtr);
    				NewPtrI.addStudent(szName,szID,szEmail,szPhone,szMajor,topStudent);				
    				break;
    			}
    		}	
    }
    
    void Student::setName(char *szName)
    {
    	strcpy(Name,szName);	
    }
    
    void Student::setID(char *szID)
    {
    	strcpy(ID,szID);
    }
    
    void Student::setEmail(char *szEmail)
    {
    	strcpy(Email,szEmail);
    }
    
    void Student::setPhone(char *szPhone)
    {
    	strcpy(Phone,szPhone);
    }
    
    void Student::setMajor(char *szMajor)
    {
    	strcpy(Major,szMajor);
    }
    
    
    void Student::setNext(Student *setnext)
    {
    	next = setnext;
    }
    
    void Student::addStudent (char *prName,char *prID,char *prEmail,char *prPhone,char *prMajor,Student *&root)
    {
      Student *ptrNewStudent;
      
      ptrNewStudent = new Student;
     
      if(ptrNewStudent != NULL)
      {
    	ptrNewStudent->Name = new char[strlen(prName)+1];
    	if(ptrNewStudent->Name != NULL)
    	{
    		ptrNewStudent->setName(prName);
    	}
    	ptrNewStudent->ID = new char[strlen(prID)+1];
    	if(ptrNewStudent->ID != NULL)
    	{
    		ptrNewStudent->setID(prID);
    	}
    	ptrNewStudent->Email = new char[strlen(prEmail)+1];
    	if(ptrNewStudent->Email != NULL)
    	{
    		ptrNewStudent->setEmail(prEmail);
    	}
    	ptrNewStudent->Phone = new char[strlen(prPhone)+1];
    	if(ptrNewStudent->Phone != NULL)
    	{
    		ptrNewStudent->setPhone(prPhone);
    	}
    
    
    	ptrNewStudent->Major = new char[strlen(prMajor)+1];
    	if(ptrNewStudent->Major != NULL)
    	{
    		ptrNewStudent->setMajor(prMajor);
    	}
    
    	if(root == NULL)
    	{
    		root = ptrNewStudent;
    	}	
    	else
    	{
    		ptrNewStudent->setNext(root);
    		root = ptrNewStudent;
    	}
      }
      else
      {
    	cerr<<"Memory Allocation Problem"<<endl;
      }
    }
    
    void showStudent(Student *root)
    {
    	Student *newStudentPtr = root;
    	
    	while(newStudentPtr != NULL)
    	{
    		cout<<newStudentPtr->getName()<<"\t"<<newStudentPtr->getID()<<"\t"<<newStudentPtr->getEmail()<<"\t"<<newStudentPtr->getPhone()<<"\t"<<newStudentPtr->getMajor()<<endl;
    		newStudentPtr = newStudentPtr->getNext();
    	}
    }
    ----------------------OutPut--------------------------
    Douglas Pepper 317581090 dpepper@iupui.edu 317-889-1090 Computer
    Science
    Lemme Goh 214889800 lgoh@iupui.edu 317-989-0999 Computer Science

    John Spine 786349000 jspine@iupui.edu 317-230-0909 Computer
    Science
    Phil Hipps 783673434 phipps@iupui.edu 317-934-9090 Physics
    Donalds Butts 984342912 dbutts@iupui.edu 317-909-1290 Computer
    Science
    Toof A Bone 888349876 tbone@iupui.edu 317-234-3212 Biology
    Joe Murphy 231892323 jmurphy@iupui.edu 365-213-9898 Chemistr
    y
    Sue Ellen 234567890 sellen@pbs.org 777-878-8234 Chemistry
    Susie Creamcheese 987654321 screamch@iupui.edu 317-999-9876
    Computer Science
    Justin Case 123456789 jcase@iupui.edu 317-222-1234 Biology

  2. #2
    Registered User The Dog's Avatar
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    OK, what you could do is this.

    Firstly change the function to this:

    void Student::addStudent (char *prName,char *prID,char *prEmail,char *prPhone,char *prMajor,Student **root)
    Note the '**'

    Then change these lines

    ptrNewStudent->setNext(root);
    root = ptrNewStudent;

    to this

    ptrNewStudent->setNext(*root);
    *root = ptrNewStudent;

  3. #3
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    Tried it Still same

    Same results

    ------------------
    Don't know what is wrong

  4. #4
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    Question do you want me to attach student.dat

    do you want me to attach student.dat

  5. #5
    Registered User The Dog's Avatar
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    ok, i'm not sure what you want to do.

    Is there addStudent function working? if not, what's it doing/not doing?

    Do you just want to add to the end of the list?

  6. #6
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    compare both of this

    Here is my data file, and the result..

    You will see that the first record in the file is last in the LinkList i want it to apper first.

    Thanks
    [comment]

    Justin Case 123456789 jcase@iupui.edu 317-222-1234 Biology
    Susie Creamcheese 987654321 screamch@iupui.edu 317-999-9876 Computer Science
    Sue Ellen 234567890 sellen@pbs.org 777-878-8234 Chemistry
    Joe Murphy 231892323 jmurphy@iupui.edu 365-213-9898 Chemistry
    Toof A Bone 888349876 tbone@iupui.edu 317-234-3212 Biology
    Donalds Butts 984342912 dbutts@iupui.edu 317-909-1290 Computer Science
    Phil Hipps 783673434 phipps@iupui.edu 317-934-9090 Physics
    John Spine 786349000 jspine@iupui.edu 317-230-0909 Computer Science
    Lemme Goh 214889800 lgoh@iupui.edu 317-989-0999 Computer Science
    Douglas Pepper 317581090 dpepper@iupui.edu 317-889-1090 Computer Science

    ------------------------------------------------------------------------------------------------------------------------
    and here are results

    Douglas Pepper 317581090 dpepper@iupui.edu 317-889-1090 Computer
    Science
    Lemme Goh 214889800 lgoh@iupui.edu 317-989-0999 Computer Science

    John Spine 786349000 jspine@iupui.edu 317-230-0909 Computer
    Science
    Phil Hipps 783673434 phipps@iupui.edu 317-934-9090 Physics
    Donalds Butts 984342912 dbutts@iupui.edu 317-909-1290 Computer
    Science
    Toof A Bone 888349876 tbone@iupui.edu 317-234-3212 Biology
    Joe Murphy 231892323 jmurphy@iupui.edu 365-213-9898 Chemistr
    y
    Sue Ellen 234567890 sellen@pbs.org 777-878-8234 Chemistry
    Susie Creamcheese 987654321 screamch@iupui.edu 317-999-9876
    Computer Science
    Justin Case 123456789 jcase@iupui.edu 317-222-1234 Biology

    [comment]

  7. #7
    Registered User The Dog's Avatar
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    >> i want it to apper first.

    OK.

    What you have to do is this:

    The first node is simple enough. After assign the first node to the root, assign NULL to the first node's next member.

    To add another node, loop through the list until the pointer's next member is NULL.

    then assign the new node to that pointer and assign NULL to the node's next member, eg.
    Code:
    Student *temp;
    temp = *root;
    if(temp)
    {    
         while(temp->next != NULL)
              temp = ptrNewStudent->next;
         temp->next = ptrNewStudent;
    }
    else
         *root = ptrNewStudent;
    using the previous code

  8. #8
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    I am having some problem fixing it in my code... Can you replace the code for me

    Thanks

  9. #9
    Registered User The Dog's Avatar
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    Change this,
    Code:
    if(root == NULL)
    {
    	root = ptrNewStudent;
    }	
    else
    {
    	ptrNewStudent->setNext(root);
    	root = ptrNewStudent;
    }
    to this
    Code:
    Student *temp;
    temp = *root;
    if(temp)
    {    
         while(temp->next != NULL)
              temp = ptrNewStudent->next;
         temp->next = ptrNewStudent;
         ptrNewStudent->next = NULL;
    }
    else
    {
         *root = ptrNewStudent;
         ptrNewStudent->next = NULL;
    }
    just declare temp in the beginning when you declare ptrNewStudent

  10. #10
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    It is still giving me memory violation error......
    Can you please complie and attach the file

    Thanks
    Pratik

  11. #11
    Registered User The Dog's Avatar
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    >> Here is my data file, and the result..

    Where?

  12. #12
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    Her is my Data file
    Attached Files Attached Files

  13. #13
    Registered User The Dog's Avatar
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    I had to make this program far harder than what it could have been because of the way you've coded it.

    Anyway, here's what you wanted:

  14. #14
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    Thumbs up Thanks

    Thank You Very Much

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