View difference between Paste ID: wjMnnYAU and 7zrVt2dv

 #include <iostream>
 #include <string>
 #include <vector>
 #include <utility>
 
 using namespace std;
 
 struct Base;
 struct A;
 struct B;
 
-	virtual void visit (Base& b) = 0;
+
-	virtual void visit (A& a) = 0;
+  virtual void visit (Base& b) = 0;
-	virtual void visit (B& b) = 0;
+  virtual void visit (A& a) = 0;
-	};
+  virtual void visit (B& b) = 0;
 };
 
-	int av;
+
-	virtual void accept (Visitor& v) { v.visit (*this); }
+  int av;
-
+  virtual void accept (Visitor& v) { v.visit (*this); }
-	Base () { av = 1;}
+  template <class VisitorType, class... Params>
   VisitorType accept (Params... args)
   {
     VisitorType v (forward <Params> (args)...);
-	int bv;
+    this->accept (v);
-
+    return v;
-	void accept (Visitor& v) { v.visit (*this); }
+  }
-
+
-	A () { av = 2; bv = 3; }
+  Base () { av = 1;}
 };
 
 struct A : public Base {
-	string cv;
+  int bv;
-
+
-	void accept (Visitor& v) { v.visit (*this); }
+  void accept (Visitor& v) { v.visit (*this); }
-
+
-	B () { av = 4; cv = "s5"; }
+  A () { av = 2; bv = 3; }
 };
-
+
 struct B : public Base {
-	void visit (Base& b) { cout << "av " << b.av << endl; }
+  string cv;
-	void visit (A& b) { cout << "bv " << b.bv << endl; }
+
-	void visit (B& b) { cout << "cv " << b.cv << endl; }
+  void accept (Visitor& v) { v.visit (*this); }
-} print;
+
   B () { av = 4; cv = "s5"; }
 };
-	vector <Base*> basev;
+
-
+
-	Base* findb (int value) {
+  void visit (Base& b) { cout << "av " << b.av << endl; }
-		static Base base; Base* pBase = &base;
+  void visit (A& b) { cout << "bv " << b.bv << endl; }
-
+  void visit (B& b) { cout << "cv " << b.cv << endl; }
-		for (int i = 0; i < basev.size (); ++i) {
+
-			if (basev[i]->av == value) return basev[i];
+
-			}
+struct Add : Visitor {
-			return pBase;
+  int av, bv;
-		}
+  Add (int av, int bv)
     : av (av), bv (bv)
   {}
   void visit (Base& b) { av += b.av; }
   void visit (A& b) { av += b.av; bv += b.bv; }
   void visit (B& b) { av += b.av; }
-d.basev.push_back (new Base);
+
-d.basev.push_back (new A);
+
-d.basev.push_back (new B);
+
   vector <Base*> basev;
-Base* found = d.findb (4);
+
   Base* findb (int value) {
-found->accept (print);
+    static Base base; Base* pBase = &base;
 
-cout << "\nDone";
+    for (int i = 0; i < basev.size (); ++i) {
       if (basev[i]->av == value) return basev[i];
     }
     return pBase;
   }
 } d;
 
 
 int main() {
 
   d.basev.push_back (new Base);
   d.basev.push_back (new A);
   d.basev.push_back (new B);
 
   Base* found = d.findb (4);
 
   found->accept <Print> ();
   int av = found->accept <Add> (0, 0).av;
 
   cout << av << "\n" << "\nDone\n";
 }