Why is there an exception thrown after inserting a new record for a doubly linked list?

[Shishykish]

Hello,

I'm making a telephone directory as practice with a double linked list data structure. When trying to select my option to insert a new record after the tail node, I have an exception thrown

Exception thrown: write access violation.
record was nullptr.

 // Exercise13.5_4revised.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <iostream>
#include <iomanip>
#include <string>

using namespace std;

struct TeleType
{
	string name;
	string phoneNo;
	TeleType *nextaddr;
	TeleType *prevaddr;
};

void populate(TeleType *); // function prototype needed by main()
void display(TeleType *); // function prototype needed by main()
void remove_head(TeleType *); //function prototype for main()
void remove_current(TeleType *); //function prototype for main()
void remove_tail(TeleType *); //function prototype for main()
void make_list();
void insert(TeleType *);
TeleType *findRec(string, TeleType *);

TeleType *phead;
TeleType *pcurrent;
TeleType *ptail;

int main()
{
	int i;
	string search_term;

	cout << "The list will now be made" << endl;

	make_list();

	cout << "\nThe list consists of the following records:\n";

	display(phead); // display the structures

	cout	<< "Which record would you like to remove?" << endl;
	cout	<< "select 1 if you want to remove the head" << endl;
	cout	<< "2 for the middle " << endl;
	cout	<< "and 3 for the tail" << endl;
	cout	<< ", 4 to insert a new record "<< endl;
	cout	<< ", 5 to find a record" << endl;
	cout	<< "6 Display records" << endl;

	cin >> i;
	cin.ignore();

	cout << endl;

	switch (i)
	{
	case 1:
		remove_head(phead);
		display(phead);
		break;
	case 2:
		remove_current(pcurrent);
		display(phead);
		break;
	case 3:
		remove_tail(pcurrent);
		display(phead);
		break;
	case 4:
		insert(ptail);
		display(phead);
		break;
	case 5:
		cout << "What are you looking for? " << endl;
		getline(cin, search_term);
		cin.ignore();
		cout << "The address matching is " << findRec(search_term, phead) << endl;
		break;
	case 6:
		display(phead);
		break;
	}

	system("pause");

	return 0;
}

void make_list()
{
	//Setting the head of the linked list
	//assign head to a new structure
	//Call populate function to fill in data
	//set nextaddr and prevaddr pointers to null
	//assign tail with head

	int number_of_records =1;
	cout << "How many records would you like?" << endl;
	cin >> number_of_records;

	TeleType head, current, temp, tail;

	TeleType *phead = &head;
	TeleType *pcurrent = &current;
	TeleType *ptemp = &temp;
	TeleType *ptail = &tail;

	populate(phead);
	head.nextaddr = NULL;
	head.prevaddr = NULL;
	tail = head;

	for (int i = 0; i < number_of_records - 1; i++)
	{
		pcurrent = new TeleType;
		populate(pcurrent);
		pcurrent->nextaddr = NULL;
		pcurrent->prevaddr = ptail;
		//ptail->nextaddr = pcurrent;
		tail = current;
	}
	//set up a for loop to make records
		//make a new node assigned to current structure
		//call populate function to fill in data members
		//assign a pointer to to current's nextaddr as NULl
		//assign pointer prevaddr of current as the pointer of head.
		//assign tail to current
	
	return;
}

// input a name and phone number
void populate(TeleType *record) // record is a pointer to a
{ // structure of type TeleType

	cout << "Enter a name: " << endl;
	getline(cin, record->name);
	cin.ignore();

	cout << "Enter the phone number: ";
	getline(cin, record->phoneNo);
	cin.ignore();

	return;
}

void display(TeleType *contents) // contents is a pointer to a
{ // structure of type TeleType

	while (contents != NULL) // display until end of linked list
	{
		cout << endl << setiosflags(ios::left)
			<< setw(30) << contents->name
			<< setw(20) << contents->phoneNo
			<< setw(20) << contents->prevaddr
			<< setw(20) << contents->nextaddr;
		contents = contents->nextaddr;
	}
	cout << endl;

	return;
}

void remove_head(TeleType *record)
{

	return;
}

void remove_current(TeleType *record)
{


	return;
}

void remove_tail(TeleType *record)
{

	return;
}

void insert(TeleType *record)
{
	TeleType *ptr_new_record = new TeleType; //create a new structure, return an address and assign it to a ptr
											 //new record.

	record->nextaddr = ptr_new_record; //change the nextaddr pointer to point to the new record

	ptr_new_record->nextaddr = NULL; //assign new null pointer
	ptr_new_record->prevaddr = record; //assign new pointer of new record to point to the the old tail structure.

	populate(ptr_new_record); //call populate function to fill in data members of the structure.

	return;
}

TeleType *findRec(string term, TeleType *contents)
{
	TeleType *pointer_to_address = phead;

	while (contents != NULL)
	{
		if (term == contents->name)
		{
			pointer_to_address = contents;
			break;
		}
		else
		{
			cout << "match not found" << endl;
		}
		contents = contents->nextaddr;
	}

	return pointer_to_address;
}

[Repeater]

In the function make_list, you create four TeleType objects. These are local to that function.

TeleType head, current, temp, tail;

They will all cease to exist when that function finishes. Any pointers to them will be pointing at garbage memory. ptail is a pointer pointing to garbage memory.