Delete All Items In A Linked List

I can't seem to figure out how to do this. The code I have in there (RemoveAll function) keeps leading to many program crashes. Please help.

Friends.h

Code:

class linkedlist {

public:

	char name[100];
	int birthday;
	int phone;
	linkedlist* nextstudent;

linkedlist ();
void Insert();
void RemoveAll();
//void Reset();
//int* GetNext();
~linkedlist ();

};

Friends.cpp

Code:

#include <iostream>
#include "friends.h"
using namespace std;

int choice = 0;
int counter = 0;

linkedlist* student;
linkedlist* headstudent;
linkedlist* prevstudent = NULL;

linkedlist functions;

linkedlist::linkedlist () {

strncpy_s(name, "No Input", 9);
birthday = 0;
phone = 0; }

void linkedlist::Insert ()
{
	student = new linkedlist;
	if (prevstudent == NULL){
		headstudent = student; }
	else {
		prevstudent->nextstudent = student; }

	cout<<"\nEnter the friend's name: ";
	cin>>student->name;
	cout<<"Enter the friend's birthday: (MMDD) ";
	cin>>student->birthday;
	cout<<"Enter the friend's phone number: (No Dashes) ";
	cin>>student->phone;

	cout<<"\n\n";

	prevstudent = student;
	prevstudent->nextstudent = NULL;
	student = headstudent;

}

void linkedlist::RemoveAll () {

	student = headstudent;

	do {
		prevstudent = student;
		student = student->nextstudent;
    	delete prevstudent;
	} while (student != NULL);

}

linkedlist::~linkedlist () {

	RemoveAll(); }

int Print()
{
	cout<<"\n\n";

	if (counter == 0) {
	cout<<functions.name<<"\nBirthday: "<<functions.birthday<<"\nPhone #: "<<functions.phone<<"\n\n"; }

	else {

	do {

		cout<<student->name<<"\nBirthday: "<<student->birthday<<"\nPhone: "<<student->phone<<"\n\n";
		student = student ->nextstudent;;
	} while (student != NULL);

	student = headstudent; }



//	for (int n = 0;n < total;n++) {  
//		cout<<"Name: "<<student->name<<"\nBirthday: "<<student->birthday<<"\nPhone #: "<<student->phone<<"\n\n"; }

	return 0;
}
int main ()
{

	while (choice != 4) {

	cout<<"Please select an option...\n\n1. Enter Data\n2. Print Data\n3. Erase All Data\n4. Quit\n\n";
	cin>>choice;

	if (choice == 1){
		functions.Insert(); }
	if (choice == 2) {
		Print(); }
	if (choice == 3) {
		functions.RemoveAll(); }

	}


	cout<<"\n";
	system("PAUSE");
	return 0;

}

node of the list and whole list are 2 different object - so it should be 2 different classes...

your concept is more C-like than C++

Why would you want two different classes?

It works fine with just one, it just crashes when I try to delete all the data stored in the list. The only problem is that something is wrong with my delete code.

That might actually be the very reason.

Do you realize that deleting a linked list node invokes the destructor of "linked-list" which in turn tries to removeAll, leading to double deletion or something like that?

You don't have a linked list. All you have are nodes that are all tied together through a horrible use of globals. A node is not a linked list. Therefore a node cannot destroy what it is part of. Only a real linked list can release all its nodes in the destructor.

Another problem is that you can't use do loops if the linked list can be empty to start with. Also, what's with the default empty linked list and a global counter that is nowhere changed and prevents from displaying the entered data.

I had no idea deleting a linked list node invoked the destructor...
I fixed that and it works better now, but crashes the second time you try to remove all data.

Default empty linked list?

The counter is supposed to change to 1 when the Insert function runs, forgot to put that in there. This is so it prints out the default values instead of crashing like it did when you tried to have it print the data before you have entered anything. My code is a mess...

We can't help furthur with the problem unless we can see what your edited code looks like.

If the list is empty, the head pointer should be NULL. You can test that and display a message (e.g "list is empty"). You don't need a overcomplicated system using even more global variables.

The crash is because you use a do loop, assuming that there is at least one node, not a while loop which can handle empty lists.