diff --git a/cpp/shared_ptr/main.cpp b/cpp/shared_ptr/main.cpp
new file mode 100644
index 0000000..b66da12
--- /dev/null
+++ b/cpp/shared_ptr/main.cpp
@@ -0,0 +1,28 @@
+#include <boost/smart_ptr.hpp>
+
+class Foo {
+  public:
+    boost::shared_ptr<Foo> s_ptr;
+    boost::weak_ptr<Foo> w_ptr;
+
+    Foo ()
+      {
+        std::cout << "Foo (): allocate big piece by " << this << std::endl;
+      }
+    ~Foo ()
+      {
+        std::cout << "~Foo (): deallocate the piece by " << this << std::endl;
+      }
+};
+
+int main (int argc, char *argv[])
+{
+  boost::shared_ptr<Foo> foo (new Foo);
+
+  if (1 < argc ? argv[1][0] - '0' : 0)
+    foo->s_ptr = boost::shared_ptr<Foo> (foo);
+  else
+    foo->w_ptr = boost::weak_ptr<Foo> (foo);
+
+  return 0;
+}