Error in linked lists

[kaaaylit]

Good evening. "cannot convert node to node** for argument 1 to void deleteNode" I encountered this error awhile ago, i get confused of this error. Can you guys help me? Thanks. This is a project in our class.

This is the code:

#include<iostream>
#include<iomanip>
#include<cctype>
using namespace std;

struct Node{
       int id;
       string fname, lname;
       Node *next;
       Node *data;
       };
       
typedef Node* NodePtr;

void displayList(NodePtr head){     //displays the list
     NodePtr p;
     p = head;
     
     while(p != NULL){
             cout << "<" << p->id << ">" << " " << p->fname << " " << p->lname << endl;
             p = p->next;
             }
     }
     
void addHead(NodePtr& head, Node newdata){   //add node at head
   NodePtr newPtr = new Node;
   newPtr->id = newdata.id;
   newPtr->fname = newdata.fname;
   newPtr->lname = newdata.lname;
   newPtr->next = head;
   head = newPtr;
}

void addMiddle(NodePtr& p, Node newdata){ //add node at middle
   NodePtr newPtr = new Node;
   newPtr->id = newdata.id;
   newPtr->fname = newdata.fname;
   newPtr->lname = newdata.lname;
   newPtr->next = p->next;
   p->next = newPtr;
}

void addEnd(NodePtr& head, Node newdata){   //add node at end
   NodePtr newPtr = new Node;
   newPtr->id = newdata.id;
   newPtr->fname = newdata.fname;
   newPtr->lname = newdata.lname;
   newPtr->next = NULL;

   NodePtr last = head;

   if(last != NULL){
      while(last->next != NULL)
          last=last->next;
      last->next = newPtr;
   }
   else
      head = newPtr;
}

NodePtr searchNode(NodePtr head, int item){ //search for nodes
   NodePtr p = head;
   NodePtr result = NULL;
   bool found=false;

   while((p != NULL) && (!found)){
      if(p->id == item) {
         found = true;
         result = p;
      }
      p = p->next;
   }
   return result;
}

void deleteNode(NodePtr* p){               //delete node
     NodePtr head, data;
     
     if(head == NULL){
             cout << "Node can't be deleted from an empty record." << endl;
             }
     else{
          NodePtr curr = head;
          NodePtr prev = NULL;
          
          while (curr != NULL){
                if(curr->data == data) break;
                else{
                     prev = curr;
                     curr = curr->next;     
                }
          }
          if (curr == 0){
                   cout << "Record not found. " << endl;
                   }     
          else{
               if (head == curr){
                        head = head->next;
                        }     
               else{
                    prev->next = curr->next;     
               }
               delete curr;
          }
     }
}    

void updateNode(NodePtr p, Node newdata){    //update nodes
     NodePtr id, fname, lname;
     p->id = newdata.id;
     p->fname = newdata.fname;
     p->lname = newdata.lname;
     }
     
void updateId(NodePtr p, Node newdata){      //update ID
     NodePtr id;
     p->id = newdata.id;
     }

void updateFname(NodePtr p, Node newdata){   //update First name
     NodePtr fname;
     p->fname = newdata.fname;
     }
     
void updateLname(NodePtr p, Node newdata){   //update Last name
     NodePtr lname;
     p->lname = newdata.lname;
     }
     
Node getId(){
     Node data;
     cout << "Enter new ID: " << endl;
     cin >> data.id;
     return data;
     }
     
Node getFname(){
     Node data;
     cout << "Enter new Firstname: " << endl;
     cin >> data.fname;
     return data;
     }
     
Node getLname(){
     Node data;
     cout << "Enter new Lastname: " << endl;
     cin >> data.lname;
     return data;
     }

Node getData(){
  Node data;

  cout << endl;
  cout << "Enter ID: ";
  cin >> data.id;
  cout << "Enter First Name: ";
  cin >> data.fname;
  cout << "Enter Last Name: ";
  cin >> data.lname;  
  cout << endl;
  
  return data;
  cout << endl;
}

main(){
  NodePtr head, p;
  Node data;
  int opt, insert, upopt; 
  
  head = p = 0;
    
 do{
    cout << setw(25) << "STUDENTS RECORD" << endl
    << "--------------------------------------" << endl      //main menu of the program
    << "|[1] Add data to the record          |" << endl
    << "|[2] View record                     |" << endl
    << "|[3] Delete data                     |" << endl
    << "|[4] Update the record               |" << endl
    << "|[0] Exit program                    |" << endl
    << "--------------------------------------" << endl
    << "Choose: ";
    cin >> opt;
    
  if (opt == 1){
             cout << setw(25) << "STUDENTS RECORD" << endl   //asks the user where to insert
    << "--------------------------------------" << endl
    << "|[1] Add record at head              |" << endl
    << "|[2] Add record at middle            |" << endl
    << "|[3] Add record at tail              |" << endl
    << "--------------------------------------" << endl
    << "Choose: ";
    cin >> insert;
      
  switch(insert){
    case 1: 
       data = getData();
       addHead(head,data);
       break;
             
    case 2:
       displayList(head);
       cout << "Insert after what ID: ";
       cin >> opt;
       p = searchNode(head,opt);

       if(p  == NULL){
         cout << "Sorry, ID not found!" << endl;       
       }
       else {
         data = getData();
         addMiddle(p,data);
       }
       break;
       
    case 3:
       data = getData();
       addEnd(head,data);
       break;
       
     default: cout << "No such option." << endl;
     }
}
 
  if (opt != 1){
    
    switch(opt){
     case 2: displayList(head); break;
     
     case 3:
          displayList(head);
          cout << "Delete what ID: " << endl;
          cin >> opt;
          p = searchNode(head, opt);
          
          if (p == NULL){
                cout << "ID not found on the list. " << endl;
                }
          else
                          deleteNode(data);
          
     case 4:
          displayList(head);
          cout << "Update what Node: ";
          cin >> opt;
          p = searchNode(head, opt);
          cout << endl;
          
          if (p == NULL){
                cout << "ID not found on the list. " << endl;
                }
          else {
                cout << "Update" << endl
                << "[1] ID" << endl
                << "[2] Firstname" << endl
                << "[3] Lastname" << endl
                << "[4] All" << endl
                << "Choice: ";
                cin >> upopt;
                
                if(upopt == 1){
                         data = getId();
                         updateId(p, data);
                         }
                else if (upopt == 2){
                         data = getFname();
                         updateFname(p, data);
                         }
                else if (upopt == 3){
                         data = getLname();
                         updateLname(p, data);
                         }
                else if (upopt == 4){
                         data = getData();
                         updateNode(p, data);
                         }
                else cout << "No such option! " << endl;
          }
          
     case 0: break;
     default: cout << "No such option!" << endl;
  }
}
  
 } while (opt != 0);
delete head, p; 

system("pause");
}

Thank you guys :D

[MiiNiPaa]

data is Node type (Line 169)
delete() takes NodePtr* type (Line 76)
NodePtr is essentially Node* (Line 13)
So delete() takes Node**
You are tying to pass Node instead of Node** (Line 241)

[kaaaylit]

What i did is that i changed the type of delete() to Node. Is that correct? Thank you! :)