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LinkListProgram crashing?

elite zero (106)
I'm having an issue with this Linked List. It runs, gets into the tokenizing function where I believe it is skipping code, then goes into the display and attempts to display "current-> lastName" which must be null, because it crashes.

Any help as to why the code would be skipping within the tokenizing function, and what can I do to fix it? 

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#include <iostream>
#include <fstream>
#include <cstdlib>
#include <stdlib.h>
#include <iomanip>
#include <sstream>
#include <stdio.h>
#include <cstddef>
#include <string.h>

using namespace std;

const int buff_size = 81; // buffer size of 81 characters

ifstream input_File;
ifstream delete_File;
int i = 0;
char *buffer = new char[buff_size], // Tokenizing pointers
     *tokens[3],
	 *ptr;

int pause; // Global for pause use

//-----------------------------------------------------------------------------

struct listNode // Structure named listNode
 {
  string age;       // Values within nodes
  string firstName;
  string lastName;
  listNode* next;
 };

listNode* newNode; // Node pointers

//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------

void reportDuplicate() // prints duplicates
 {
  cout << "Duplicate Record: " << newNode-> lastName << endl;
 }// end void reportDuplicate()

//-----------------------------------------------------------------------------

void incompleteRecord()
{
 cout << "Record incomplete: " << tokens[0] << endl;
}// end void incompleteRecord()

//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------

void insertName(char tokens[0])
{

 // Initializes list on insertion
 // Creates new node and inserts tokenized values

 newNode = new listNode;
 newNode-> lastName = tokens[0];
 newNode-> next = NULL;

 listNode* head;
 listNode* current = head; // set traversal pointer

 if(head == NULL) // If no head node, create one
  {
   head = newNode;
   newNode-> next = NULL;
  }
 else if(head-> lastName > newNode-> lastName)
  {
   newNode-> next = head;
   head = newNode;
  }

 else
  {
   while((current-> next != NULL) && (current-> next-> lastName < newNode-> lastName)) // Traverse the list
   {
	if(current-> lastName == newNode-> lastName)
	 {
	  reportDuplicate();
	 }
	else
	 {
	  current = current-> next;
	 }
   }
	 
	if(current-> lastName < newNode-> lastName)
	 {
	  newNode-> next = current-> next;
	  current-> next = newNode;
	 }

   }//end if(lastName)
}//end void insertName(...)

//-----------------------------------------------------------------------------

void tokenizingFunction()
 {
	 cout << "Tokenizing..." << endl << endl;

    while(input_File.getline(buffer, buff_size))
     {
	  cout << "1" << endl;
      // If we found a blank line (newline char in column 1), ignore it and 
      // continue. 

	  cout << buffer << endl;

      if(strlen(buffer) == 0)
	   continue;
      
	  // ** Windows Machines Only **
      // Break the input string into white space separated tokens.
	  // 3rd parameter needs to be a char**_Context
      // Use char* (placeHolder) as a place holder within the string (used in strtok_s)
	  // Format: ptr = (char *)strtok_s(buffer, " ", &placeHolder);

      ptr = (char *)strtok(buffer, " ");

      // If ptr == NULL, then other than whitespace, the input line is
      // empty.
    
      if(!ptr)
	   continue;
      
      // Store the tokens in tokens[]

      i = 0;

      tokens[i] = (char *)strdup(ptr);

      do
	   {
        ptr = (char *)strtok('\0', " "); 

         if(ptr)
          {
           tokens[++i] = (char *)strdup(ptr);
          }
		 
       }
      while(ptr); 

	  // char* tokens[0] contains string lastName
	  // char* tokens[1] contains string firstName
	  // char* tokens[2] contains string ages
	   
	  cout << tokens[0] << endl;

      insertName(tokens[0]); // Insert
	   
	  
	 }

  delete(buffer);
 } // end void tokenizingFunction()

//-----------------------------------------------------------------------------

  // Possible node activity //

  // newNode-> lastName;   -value of lastName
  // newNode-> firstName;  -value of firstName
  // newNode-> age;        -value of age
  // newNode-> next;       -pointer to next node

//-----------------------------------------------------------------------------

void displayList()
{

 listNode* head;
 listNode* current;

 cout << "\nDisplaying List" << endl << endl;

 current = head;
 cout << "A" << endl;
 
  while(current != NULL)
   {
	   cout << "B" << endl;
    if(current == NULL)
     {
	  cout << "\nEnd of list!" << endl;
     }
    else
     {
		 cout << "C" << endl;
	  cout << current-> lastName << endl;
	     cout << "D" << endl;
	  current = current-> next;
     }
   
  }// end while
}// end void displayList()

//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------

int main(int argc, char *argv[])
{

if(argc != 2)	// Usage statement
 {
  cout << "\nUsage: " << argv[0] << " 'Input File Name 1'" <<  endl;
  return(0);
 }

//--------------------------- ifstreams

ifstream input_File(argv[1], ios::in);	// Open input file to read from
 if(input_File.is_open())
  {
   cout << "\nInput File is open..." << endl;
  } 
 else
  {
   cout << "\nInput File did NOT open..." << endl;
   return (1);
  }


//-----------------------------------------------------------------------------

// Functions

listNode* head = NULL; // Initialize head pointer

if(input_File.is_open())
{
 if(input_File.good())
  {
   tokenizingFunction(); // tokenizes and inserts into list
  }
}

displayList();

//-----------------------------------------------------------------------------
 
  cin >> pause; // Non Windows Pause similar to (system("pause");)
  return 0;
}


elite zero (106)
Sorry for all of the "cout" statements, just trying to error check the code and see where it is working towards.

So far, this is what prints.

Input File is open...
Tokenizing...

Displaying List

A
B
C

....crash
TheIdeasMan (6817)
http://en.cppreference.com/w/cpp/iterator/next


That might be causing a clash with the std namespace you have on line 11, and your next variable.

Also, there is a bit of a convention to declare functions before main, then put their definitions after main().

Have you thought about using a debugger? It will show where it is going wrong fairly quickly.

HTH
elite zero (106)
I have used a debugger, however, in a rare set of circumstances with a professor of mine, I use a Window's based machine, and he uses Mac and vim. If I use Visual Studio and attempt to debug it, I have to use Window's version of strtok which is strtok_s. If I use strtok_s, it will not compile on his machine. I have this program working with strtok_s via Visual Studio(added below) however, when I changed it, it stopped running.

Visual Studio running code:
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#include <iostream>
#include <fstream>
#include <cstdlib>
#include <stdlib.h>
#include <iomanip>
#include <sstream>
#include <stdio.h>
#include <windows.h>
#include <cstddef>
#include <string.h>

using namespace std;

const int buff_size = 81; // buffer size of 81 characters

ifstream input_File;
ifstream delete_File;

int i = 0;
char *buffer = new char[buff_size], // Tokenizing pointers
     *tokens[3],
	 *ptr,
	 *placeHolder;

string firstN; // Global variables
string lastN;
string ages;
int pause;

//-----------------------------------------------------------------------------

struct listNode // Structure named listNode
 {
  string age;       // Values within nodes
  string firstName;
  string lastName;
  listNode* next;
 };

listNode* newNode; // Node pointers
listNode* head;
listNode* current;

//-----------------------------------------------------------------------------

void initializeList() // sets pointers
 {
  listNode* head = NULL;
  listNode* current = head;
 }

//-----------------------------------------------------------------------------

void reportDuplicate() // prints duplicates
 {
  cout << "Duplicate Record: " << newNode-> lastName << endl;
 }

//-----------------------------------------------------------------------------

void incompleteRecord()
{
 cout << "Record incomplete: " << tokens[0] << endl;
}// end void incompleteRecord()

//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------

void insertName(string lastN)
{

 // Initializes list on insertion
 // Creates new node and inserts tokenized values

 newNode = new listNode;
 newNode-> lastName = lastN;
 newNode-> next = NULL;

 listNode* current = head; // set traversal pointer

 if(head == NULL) // If no head node, create one
  {
   head = newNode;
   newNode-> next = NULL;
  }
 else if(head-> lastName > newNode-> lastName)
  {
   newNode-> next = head;
   head = newNode;
  }

 else
  {
   while((current-> next != NULL) && (current-> next-> lastName < newNode-> lastName)) // Traverse the list
   {
	if(current-> lastName == newNode-> lastName)
	 {
	  reportDuplicate();
	 }
	else
	 {
	  current = current-> next;
	 }
   }
	 
	if(current-> lastName < newNode-> lastName)
	 {
	  newNode-> next = current-> next;
	  current-> next = newNode;
	 }

   }//end if(lastName)
}//end void insertName(...)

//-----------------------------------------------------------------------------

void tokenizingFunction()
 {
    while(input_File.getline(buffer, buff_size))
     {
      // If we found a blank line (newline char in column 1), ignore it and 
      // continue. 

      if(strlen(buffer) == 0)
	   continue;
      
      // Break the input string into white space separated tokens.
	  // 3rd parameter needs to be a char**_Context
      // Use char* (placeHolder) as a place holder within the string (used in strtok_s)

      ptr = (char *)strtok_s(buffer, " ", &placeHolder); // Remember to change this for Mac

      // If ptr == NULL, then other than whitespace, the input line is
      // empty.
    
      if(!ptr)
	   continue;
      
      // Store the tokens in tokens[]

      i = 0;

      tokens[i] = (char *)_strdup(ptr);

      do
	   {
        ptr = (char *)strtok_s('\0', " ", &placeHolder); // Remember to change this for Mac 

         if(ptr)
          {
           tokens[++i] = (char *)_strdup(ptr);
          }
		 
       }
      while(ptr); 

	  lastN = tokens[0];  // string lastN
	  firstN = tokens[1]; // string firstN
	  ages = tokens[2];   // string ages 

	   if(buffer && tokens[2]) // Not a blank line, and token[2] has token
	   {
        insertName(lastN); // Insert
	   }
	  
	 }

  delete(buffer);
 } // end void tokenizingFunction()

//-----------------------------------------------------------------------------

  // Possible node activity //

  // newNode-> lastName;   -value of lastName
  // newNode-> firstName;  -value of firstName
  // newNode-> age;        -value of age
  // newNode-> next;       -pointer to next node

//-----------------------------------------------------------------------------

void displayList()
{
 cout << "\nDisplaying List" << endl << endl;

 current = head;

  while(current != NULL)
   {
    if(current == NULL)
     {
	  cout << "\nEnd of list!" << endl;
     }
    else
     {
	  cout << current-> lastName << endl;
	  current = current-> next;
     }
   
  }// end while
}// end void displayList()

//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------

int main()//int argc, char *argv[])
{
   // Open input stream files for use without argc / argv ------ delete before turning in
   input_File.open("InputNameList.txt");
   // delete_File.open("deleteThese.in");


  
/*if(argc != 3)	// Usage statement of how to use program via command line
 {
  cout << "\nUsage: " << argv[0] << " 'Input File Name 1'" << " 'Input File Name 2'\n" <<  endl;
  return(0);
 }

//--------------------------- ifstreams

ifstream input_File(argv[1], ios::in);	// Open first input file to read from
 if(input_File.is_open())
  {
   cout << "\nInput File is open..." << endl;
  } 
 else
  {
   cout << "\nInput File did NOT open..." << endl;
   return (1);
  }

ifstream delete_File(argv[2], ios::in);	// Open second input file to delete from
 if(delete_File.is_open())
  {
   cout << "\nDelete File is open..." << endl;
  }
 else 
  {
   cout << "\nDelete File is NOT open..." << endl;
   return (1);
  }*/

//-----------------------------------------------------------------------------

// Functions

initializeList(); // Initializes head, current, and prev_Ptr
if(input_File.is_open())
{
 while(input_File.good())
  {
   while(!input_File.eof())
    {
     tokenizingFunction(); // tokenizes and inserts into list
    }
  }
}
else
{
 cout << "Input File is NOT Open!" << endl << endl;
 system("pause");
 return (1);
}


displayList();

//-----------------------------------------------------------------------------
 
  cin >> pause; // Non Windows Pause similar to (system("pause");)
  return 0;
}
elite zero (106)
This one is hard coded for file input, and uses global variables and unnecessary movement of strings from tokens to lastName, but it works.
TheIdeasMan (6817)
Hi,

Do you have to use char arrays and strtok at all?

Why not std::string and it's member functions & algorithms (maybe they are not allowed for your assignment?)

Also this link for stringstreams:

http://stackoverflow.com/questions/289347/using-strtok-with-a-stdstring


elite zero (106)
The char arrays and strtok is actually the professors code and he advised us to use it. The entire tokenizing function is his.
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