CODEWITHSUNDEEP
c++linked-list
Berk
Berk

Reputation: 120

C++ linked list weird outputs

So i've been trying to code a linked list. When i debug or if i put one more print statement like this;

intlist.add_node(7);
intlist.print_list();
intlist.add_node(8);

It works fine prints; 

5
7
5
7
8

But if i remove that statement, it only prints three eights. Same goes for debugging, it seems working but if i just run it doesn't. I didn't understand what is wrong. Here's my main;

int main(){
  Linked_list intlist;
  intlist.add_node(5);
  intlist.add_node(7);
  intlist.print_list();
  intlist.add_node(8);
  intlist.print_list();
  return 0;
}

header;

class Linked_list{
public:
  Linked_list();

  void add_node(int data);
  void remove_node(int data);
  int get_data(int index);
  void print_list();

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

  Node* head;
  int lenght;
};

And header's source file;

Linked_list::Linked_list(){
  head = 0;
  lenght = 0;
}

void Linked_list::add_node(int data){
  Node* newnode = new Node;
  newnode->data = data;
  newnode->next = NULL;
  if (head == 0) {head = newnode; lenght = 1; return;}
  else{
      Node* temp = new Node;
      temp = head;
      while (temp->next != NULL){
          temp = temp->next;

      }
      lenght++;
      temp->next = newnode;
      delete temp;
  }
}


void Linked_list::remove_node(int data){
    return;
}

int Linked_list::get_data(int index){
    return 0;
}

void Linked_list::print_list(){
    if (head == 0) {std::cout << "List is empty!!" << std::endl; 
    return;}
    else{
        Node* ptr = new Node;
        ptr = head;
        for (int i = lenght; i > 0; i--){
            std::cout << ptr->data << std::endl;
            ptr = ptr->next;
        }
    }
}

Upvotes: 2

Views: 55

Answers (1)

bchetioui
bchetioui

Reputation: 326

Your add_node function should be:

void Linked_list::add_node(int data) {

  Node* newnode = new Node;
  newnode->data = data;
  newnode->next = NULL;

  if (head == 0) {
      head = newnode;
      lenght = 1;
      return;
  } else {
      //Node* temp = new Node;
      Node *temp = head;
      while (temp->next != NULL) {
          temp = temp->next;
      }

      lenght++;
      temp->next = newnode;
      //delete temp;
  }
}

You don't need to create a new Node object since you are only looking to reference head. delete temp actually deletes the content of the address previously pointed to by temp, which is the last element of your list.

Upvotes: 4

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