#include "Object.h"
#include "Entry.h"
class Node: public Entry{
  Node(int type,int size, Entry *entryArr[],Node *link);
 //abstract methods
   virtual  bool isFull();
   virtual string toString();
 //public methods
  string toStringSimple();
  Entry* insert(Entry  *entry);
  StudentRecord* treeSearch(int searchKey);
  StudentRecord* leafSearch(int searchKey);
  void insertIntoNode(Entry *entry);
  //int getNumberOfInteriorNodes();
  int splitIndex();
  int depth();
 //accessors and mutators
  Node* getLink();
 //static methods
  static void setSizes(int m, int n);
  int type;
  int size;
  Entry *entryArr[];
  Entry *entry;
  Node *link;
  int maxSize;
  static const int LEAF = 0;
  static const int INTERNAL = 1;
  static const int MAX_INTERNAL_SIZE;
  static const int MAX_LEAF_SIZE;
 //private methods
  Entry* split();
 friend class InteriorNode;
 friend class LeafNode;

'Entry' has not been declared
ISO C++ forbids declaration of Entry with no type

It's kind of hard to see what's wrong unless you post more code, more specifically, "Entry.h"...