Linked List Print

[thomaselder84]

The program I'm currently writing uses a linked list. When the the program first starts, the current list needs to print 1 element with the value '0'. This happens before the user has added anything to it. I tried editing my current Print method to accomplish this, but it's not printing anything out. The print method still works after I manually enter in elements. Just can't get the initial print to work. Here's what I tried.

 void LList::Print(){

	//PreConditions: The native object LList is valid
	//PostConditions: The native object LList is unchanged and its elements
	//                have been displayed

	listnode * temp;


	
	if (head != NULL)
		temp = head;
	else{
			temp = new listnode;
			temp->data = 0;
			temp->next = NULL;
			head = temp;
		}
																					
	while (temp != NULL){
		cout << temp->data;
		temp = temp->next;
	}

}

[Gamer2015]

//PreConditions: The native object LList is valid

When is the list not valid?

//PostConditions: The native object LList is unchanged and its elements
// have been displayed

This condition tells us to mark the function const (marked bold)
So, if there is no element in there you don't want a Node to be created in the List, right?
in that case, you should remove the head = temp; after creating a new listnode
also, you can only just print "0" and return if you don't want to add an empty element :b

i still don't understand what you mean by print 1 element with value 0 if the List is empty

the rest of the print method looks fine.

void LList::Print() const 
{
    //PreConditions: The native object LList is valid
    //PostConditions: The native object LList is unchanged and its elements
    //                have been displayed

    if(head == NULL)
    {
        std::cout << '0' << std::endl; // print 0, but not not modifying LList
        return;
    }

    listnode* temp = head;
			
    while (temp != NULL) 
    {
	cout << temp->data;
	temp = temp->next;
    }

}

[thomaselder84]

Thanks. I wasn't really thinking about the post conditions when attempting to solve this.

As to your question, it doesn't necessary need to be a listnode. When the user hasn't entered anything yet, I need to print "Current List: 0". So, your solution works. Thanks