View difference between Paste ID: vMVTHM9h and HSccZQ3d

 #include <iostream>
 #include <vector>
 
 using namespace std;
 
-class Base;
+
-class A;
+
-struct BaseVisitor
+  virtual bool is (int value) const
-{
+  {
-  virtual void visit (Base&) = 0;
+    return av == value;
-  virtual void visit (A&) = 0;
+
   virtual void print() const
   {
     cout << av << endl;
-  virtual void accept (BaseVisitor& v) {
+
-    v.visit (*this);
+
 
 struct A : public Base {
   int bv;
   virtual bool is (int value) const
   {
-  virtual void accept (BaseVisitor& v) {
+    return bv == value;
-    v.visit (*this);
+
   virtual void print () const
   {
     cout << bv << endl;
-struct ValueFinder: public BaseVisitor {
+
-  int value;
+
-  bool found;
+
-  ValueFinder (int value) : value(value) {}
+
-  virtual void visit (Base& b) {
+
-    found = value == b.av;
+
   database () { NBase.av = 0; }
-  virtual void visit (A& b) {
+
-    found = value == b.bv;
+
     for (int i = 0; i < basev.size (); ++i) {
       if(basev[i]->is (value));
 	return basev[i];
     }
     return &NBase;
   }
 } db;
 
 int main( ) {
 
-    ValueFinder finder(value);
+
   der.av = 5;
-      basev[i]->accept (finder);
+
-      if(finder.found)
+
   Base* found = db.findb (5);
   found->print ();
 }