How do I pass variable to function?

[georgieboy]

Hey guys, so I am trying to build a simple Linked List (Just practice NOT a homework assignment). I managed to make it without the use of functions but then my main was pretty long. So now I am trying to condense it into by using some function calls. My question is, how do I get my display function to work after I have inserted my values in my list.

 #include <iostream>

using namespace std;

struct node{
	int data;
	node *next;
};

void insert(int, node*);
void display(node*); 

int main(){
	int x = 0;
	node *myNode = 0;

	while(x != -1){
		cout << "please enter a number: ";
		cin >> x;

		if(x == -1){
			cout << "good bye!" << endl;
		}

		else{
			insert(x, myNode);
		}
	}
	display(myNode);

	system("pause");
	return 0;
}

void insert(int x, node *temp){
	node *head = NULL;

	temp = new node;
	temp->data = x;
	temp->next = head;
	temp = head;
}

void display(node *myNode){ //I can't seem to get my function to read in temp^^

	while(myNode != NULL){
		cout << myNode->data << " ";
		myNode->next = myNode;
	}
}

[vlad from moscow]

Your function insert is invalid.

[AbstractionAnon]

myNode is your list head. You need to pass it to insert as a pointer to a pointer, or as a pointer by reference.

You have head and temp reversed. head needs to be the argument and temp should be the local variable.

The assignment in line 41 is reversed.

[vlad from moscow]

Try the following code.

#include <iostream>
#include <cstdlib>

using namespace std;

struct node
{
	int data;
	node *next;
};

void insert( node **, int );
void display( node ** ); 
void clear( node ** );

int main()
{
	int x;
	node *head = 0;

	while ( true )
	{
		cout << "please enter a number: ";
		cin >> x;

		if ( !cin || x == -1 )
		{
			cout << "good bye!" << endl;
			break;
		}

		insert( &head, x );
	}

	display( &head );

	clear( &head );


	system( "pause" );
	return 0;
}

void insert( node **head, int x )
{
	node *temp = new node;
	temp->data = x;
	temp->next = *head;
	*head = temp;
}

void display( node **head )
{ 
	for ( node *n = *head; n != NULL; n = n->next )
	{
		cout << n->data << " ";
	}
} 

void clear( node **head )
{ 
	while ( node *n = *head  )
	{
		*head = ( *head )->next;
		delete n;

	}
}