Thread: Rate my doubly linked list class and its functions

So, I've been trying to implement a doubly linked list in C but I ran into trouble when I tried to delete the first element of the list. Looked up C++ classes and such and decided to rewrite it as a class. And it seems to work a bit better now.

Anyone feel like going over this one with a critical eye? :>

EDIT: (Hope it's not too much code)

Code:

#include <iostream>

using namespace std;

class list {
  private:
    struct member {
      int ID;

      member *next;
      member *prev;
    };

    int nextID;

    member *start;
    member *link;
    member *end;
    
    list operator = (list);

  public:
    list() {
      start = link = end = NULL;
      nextID = 0;
    }

    ~list() {
      if(listExists()) {
        wipeList();
      }
    }

    void addLink();
    void delLink(int ID);
    void delStart();
    void delEnd();
    void wipeList();
    void printLinkID();
    bool nextLink();
    bool prevLink();
    bool seekLink(int ID);
    bool listExists();
};

bool list::listExists() {
  if(start != NULL) {
    return true;
  }
  
  return false;
}

void list::wipeList() {
  while(listExists()) {
    delStart();
  }
}

void list::delStart() {
  member *temp;

  if(listExists()) {
    temp = start;
    
    if(start->next != NULL) {
      start = start->next;
      start->prev = NULL;
    } else {
      start = NULL;
    }
    
    delete temp;
  }
}

void list::delEnd() {
  member *temp;
  
  if(listExists()) {
    temp = end;
    
    if(end->prev != NULL) {
      end = end->prev;
      end->next = NULL;
    } else {
      end = NULL;
    }
    
    delete temp;
  }
}

void list::delLink(int ID) {
  member *temp;

  if(seekLink(ID)) {
    if(link->next != NULL) {
      if(link->prev != NULL) {
        link->prev->next = link->next;
        link->next->prev = link->prev;
      } else {
        link->next->prev = NULL;
        start = link->next;
      }

      temp = link;
      link = link->next;
      delete temp;
    } else {
      temp = link;
      end = link->prev;
      end->next = NULL;
      delete temp;
    }
  }
}

void list::addLink() {
  if(listExists()) {
    member *newLink = new member;

    if(link->next != NULL) {
      newLink->next = link->next;
    } else {
      end = newLink;
    }

    newLink->prev = link;
    newLink->ID = nextID++;
    link->next = newLink;
  } else {
    start = new member;
    link = end = start;

    start->prev = start->next = NULL;

    link->ID = nextID++;
  }
}

bool list::seekLink(int ID) {
  link = start;

  do {
    if(link->ID == ID) {
      return true;
    }
  } while(nextLink());

  return false;
}

void list::printLinkID() {
  if(listExists()) {
    link = start;

    cout << "List Exists!" << endl;

    do {
      cout << link->ID << endl;
    } while(nextLink());
  } else {
    cout << "List does not exist!" << endl;
  }
}

bool list::nextLink() {
  if(link->next != NULL) {
    link = link->next;

    return true;
  }

  return false;
}

bool list::prevLink() {
  if(link->prev != NULL) {
    link = link->prev;

    return true;
  }

  return false;
}

int main() {
  list test;
  int i;

  for(i = 0; i < 10; i++) {
    test.addLink();
    test.nextLink();
  }
  
  test.printLinkID();
  
  cout << endl;
  
  test.delLink(0);
  test.delLink(4);
  test.delLink(9);
  
  test.printLinkID();
  
  cout << endl;
  
  test.delStart();
  test.delStart();
  test.delStart();
  test.delStart();
  test.delStart();
  test.delStart();
  test.delStart();
  test.delStart();
  
  test.printLinkID();
  
  return 0;
}