Help with C++, linked lists

Hi guys,

I'm trying to write a program that stores a name, ID number, average test score, and letter grade for up to 20 students. This code here will only store/print one student's information. I can't figure out how to get it to store more than that. Any advice?

Code:

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#include <iostream>
using namespace std;

struct node
  {  char name[20];                // Name of up to 20 letters
    int idNum;     
    int avgScore[20];   
        char grade[20];
    node *nxt;                        // Pointer to next node
  };

node *start_ptr = NULL;
node *current;                // Used to move along the list
int option = 0;

void add_record()
  {  node *temp, *temp2;  // Temporary pointers
        //node avgScore;
    // Reserve space for new node and fill it with data
        int* a = NULL;  // Pointer to int, initialize to nothing.
        int n;          // Size needed for array
        cout << "\n\t--------------Student Information---------------\n";
        cout << "How many test scores this semester? ";
        cin >> n;        // Read in the size
        a = new int[n];  // Allocate n ints and save ptr in a.
        for (int i=0; i<n; i++)
        {
                a[i] = 0;    // Initialize all elements to zero.
        }
   
        int m;
        cout << "How many students in the course? ";
        cin >> m;
        temp = new node;
        for (int k=0; k<m; k++)
        {
                cout << "Please enter the name of student " << (k+1) << ": ";
                cin >> temp->name;
                cout << "Please enter the ID Number of the student : ";
                cin >> temp->idNum;
                cout << "Please enter student's test scores for the " << n << " tests: ";
                for (int j=0; j<n; j++)
                {
                        cout << "\nTest " << (j+1) << ": ";
                        cin >> a[j];
                        /*for (int p=0; p<j; p++)
                        {
                                temp->avgScore = (temp->avgScore + a[p]) / p;
                        }*/
                }

        }

    temp->nxt = NULL;

    // Set up link to this node
    if (start_ptr == NULL)
      { start_ptr = temp;
        current = start_ptr;
      }
    else
      { temp2 = start_ptr;
        // We know this is not NULL - list not empty!
        while (temp2->nxt != NULL)
          {  temp2 = temp2->nxt;
              // Move to next link in chain
          }
        temp2->nxt = temp;
      }
  }

void display_list()
  {  node *temp;
    temp = start_ptr;
    cout << endl;
    if (temp == NULL)
      cout << "List currently empty." << endl;
    else
      { while (temp != NULL)
          {  // Display details for what temp points to
              cout << "Name : " << temp->name << " ";
              cout << "idNum : " << temp->idNum << " ";
                          cout << "avgScore : " << temp->avgScore;
              if (temp == current)
                cout << " <-- Current node";
              cout << endl;
              temp = temp->nxt;

          }
        cout << "End of list!" << endl;
      }
  }

void main()
  {  start_ptr = NULL;

    do
        {
          display_list();
          cout << endl;
          cout << "Please select an option : " << endl;
         
          cout << "1. Create new record." << endl;
          cout << "2. Exit the program." << endl;

          cin >> option;

          switch (option)
            {
              case 1 : add_record(); break;
            }
        }
    while (option != 2);
  }

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I know not all the steps are there for everything, my main concern is how to get it to store/print more than one student. I appreciate any responses.

Thanks!

Well it seems you're struct Node shouldn't contain arrays for the values.

You should have a Node like this:

Code:

---


struct Node{

  string name;
  int idNum;     
  int avgScore;   
  char grade;
  Node *nxt;
};

---

Then you want to make a list of these structs.

And get rid of the global pointers to the struct ( actually you don't need global variables at all ).


Also consider initializing all of node's attributes in a constructor like this:

Code:

---


struct Node{

  string name;
  int id;
  int avg;
  char grade;
  Node* nxt;

  // Constructor initialization list:
  Node( string n, int i, int a, char g, Node* nx = 0 )
  : name( n ), id( i ), avg( a ), grade( g ), nxt( nx ) {}

};

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This will make your code a lot clearer when you write the rest of your funcitons.