Linked List - Inserting In Order

[mrchaos]

so far my code is as below. I need to insert records in order and I'm not sure how to.

The program contains pre-defined data which is inserted when the program runs, but it also accepts user input which needs to put in order according to the student number.

thanks

#include <iostream>
#include <string>
#include <stdlib.h>
struct  link {
   int stnum;
   string name;
   link *next;
};

class linklist {
   private:
      link *first;
   public:
      linklist() {
         first = NULL;
      }
      void additem(int s, string n);
      void display();
      void insertitem(int s, string n);
};

void linklist::additem(int s,string n) {
   link * newlink = new link;
   newlink -> stnum = s;
   newlink -> name = n;
   newlink -> next = first;
   first = newlink;
}

void linklist::insertitem(int s,string n) {
   link * newlink = new link;
   newlink -> stnum = s;
   newlink -> name = n;
   newlink -> next = first;
   first = newlink;
   
}

void linklist::display() {
   link *current = first;
   while(current != NULL) {
      cout << current->stnum << "   " << current->name <<endl;
      current = current -> next;
   }
}

int main() {
   linklist li;
   li.additem(1315,"Mary");
   li.additem(1307,"John");
   li.additem(1293,"Kim");
   li.additem(1270,"Marty");
   li.additem(1258,"Linda");
   li.display();
   cout << endl << "Add Students - '0' to end" << endl;
   string student;
   int studentnum;
   while (student != "0") {
      cout << "Student Name: ";
      cin >> student;
      if (student != "0") {
         cout << "Student Number: ";
         cin >> studentnum;
         cout << endl;
         li.insertitem(studentnum,student);
     }
   }

   cout << endl;
   li.display();
   cin.ignore();
   cin.get();
   return 0;
}