View difference between Paste ID: HSccZQ3d and LDsD7Atn

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