diff --git a/test_new_delete.cpp b/test_new_delete.cpp
new file mode 100644
index 0000000..4feb1b2
--- /dev/null
+++ b/test_new_delete.cpp
@@ -0,0 +1,151 @@
+#include <malloc.h>
+#include <iostream>
+#include <exception>
+#include <string>
+
+
+struct A
+{
+	std::string s;
+
+	A()
+	{}
+
+	virtual ~A()
+	{}
+
+	void * operator new (size_t s)
+	{
+		std::cout << "A::operator new: size=" << s << std::endl;
+		return malloc( s );
+	}
+
+	void operator delete (void * p)
+	{
+		std::cout << "A::operator delete: p=" << p << std::endl;
+		free(p);
+	}
+};
+
+struct B : public A
+{
+	std::string b;
+};
+
+struct C : public A
+{
+	std::string c;
+	
+	void * operator new (size_t s)
+	{
+		std::cout << "C::operator new: size=" << s << std::endl;
+		return malloc( s );
+	}
+
+	void operator delete (void * p)
+	{
+		std::cout << "C::operator delete: p=" << std::hex << p << std::endl;
+		free(p);
+	}
+};
+
+struct D : public B, public C
+{
+	//
+	//	You should define this otherwise new/delete are ambiguous.
+	//
+	void * operator new (size_t s)
+	{
+		std::cout << "D::operator new: size=" << s << std::endl;
+		return malloc( s );
+	}
+
+	void operator delete (void * p)
+	{
+		std::cout << "D::operator delete: p=" << std::hex << p << std::endl;
+		free(p);
+	}
+};
+
+struct F : public A
+{
+	std::string str;
+};
+
+struct E : public B, public F
+{
+};
+
+
+void * operator new ( size_t s, const std::string& str )
+{
+	std::cout << str << std::endl;
+	return malloc( s );
+}
+
+
+int main ( void )
+{try{
+	A * a;
+
+	//
+	//	Operator inheritance.
+	//
+	std::cout << std::hex << std::showbase << std::endl;
+	std::cout << " Operator inheritance." << std::endl;
+	std::cout << "===============================================" << std::endl;
+	std::cout << "allocate and free A." << std::endl;
+   	a = new A;
+	delete a;
+	
+	std::cout << "allocate and free B." << std::endl;
+   	a = new B;
+	delete a;
+
+	std::cout << "allocate and free C." << std::endl;
+   	a = new C;
+	delete a;
+
+	std::cout << "allocate and free D." << std::endl;
+	D * d = new D;
+	std::cout << "D=" << d << " B=" << (B*)d << " C=" << (C*)d << std::endl;
+   	a = (C*)d;
+	delete a;
+
+	std::cout << "allocate and free E." << std::endl;
+   	E * e = new E;
+	std::cout << "E=" << e 
+			<< " B=" << (B*)e 
+			<< " BA=" << (A*)(B*)e 
+			<< " F=" << (F*)e 
+			<< " FA=" << (A*)(F*)e << std::endl;
+	a = (F*)e;
+	delete a;
+
+	//
+	//	In place new.
+	//
+	std::cout << std::endl;
+	std::cout << std::endl;
+	std::cout << std::endl;
+	std::cout << " In place new." << std::endl;
+	std::cout << "===============================================" << std::endl;
+	int * i = new (std::string("Hello")) int;
+
+	std::cout << std::endl;
+	std::cout << std::endl;
+	return 0;
+}
+catch ( const std::exception& e )
+{
+	std::cerr << std::endl
+			<< "std::exception(\"" << e.what() << "\")." << std::endl;
+	return 2;
+}
+catch ( ... )
+{
+	std::cerr  << std::endl
+			<< "unknown exception." << std::endl;
+	return 1;
+}}
+
diff --git a/test_placement_new.cpp b/test_placement_new.cpp
deleted file mode 100644
index b1dddc0..0000000
--- a/test_placement_new.cpp
+++ /dev/null
@@ -1,31 +0,0 @@
-#include <malloc.h>
-#include <iostream>
-#include <exception>
-
-
-void * operator new ( size_t s, const std::string& str )
-{
-	std::cout << str << std::endl;
-	return malloc( s );
-}
-
-
-int main ( void )
-{try{
-
-	int * i = new (std::string("Hello")) int;
-	return 0;
-}
-catch ( const std::exception& e )
-{
-	std::cerr << std::endl
-			<< "std::exception(\"" << e.what() << "\")." << std::endl;
-	return 2;
-}
-catch ( ... )
-{
-	std::cerr  << std::endl
-			<< "unknown exception." << std::endl;
-	return 1;
-}}
-