Finished exercise 01, possible memory leak ?

exercise/01/animal.cpp

@@ -0,0 +1,43 @@
+#include "animal.h"
+
+leg_counter::leg_counter() : number_of_legs (0)
+{
+}
+
+leg_counter::~leg_counter() 
+{
+}
+
+animal& leg_counter::add_animal (animal& a) 
+{
+	number_of_legs += a.legs();
+	return a;
+}
+
+unsigned int leg_counter::legs() 
+{
+	return number_of_legs;
+}
+
+animal& animal_factory(int id) 
+{
+	animal* a = nullptr;
+
+	/*----------------------------------memory leak ???????------------------------------
+	*/
+	switch (id) 
+	{
+	case 1:
+		a = new cockroach;
+		break;
+	case 2:
+		a = new sparrow;
+		break;
+	case 3:
+		a = new tarantula;
+		break;
+	}
+
+	return *a;
+
+}

exercise/01/animal.h

@@ -0,0 +1,63 @@
+#pragma once
+class animal 
+{
+public:
+	virtual animal& species() = 0;
+	virtual const wchar_t* c_str() = 0;
+	virtual const unsigned int legs() = 0;
+};
+
+class insect : public animal
+{
+public:
+	//virtual const wchar_t *c_str() override { return L"insect"; }
+	animal& species() override { return *this; }
+};
+
+class bird : public animal
+{
+public:
+	//virtual const wchar_t* c_str() override { return L"bird";}
+	animal& species() override { return *this; }
+};
+
+class spider : public animal 
+{
+public:
+	//virtual const wchar_t* c_str() override { return L"spider"; }
+	animal& species() override { return *this; }
+};
+
+class cockroach : public insect 
+{
+public:
+	const wchar_t* c_str() override { return L"cockroach"; }
+	const unsigned int legs() override { return 6u; }
+};
+
+class sparrow : public bird 
+{
+public:
+	const wchar_t* c_str() override { return L"sparrow"; }
+	const unsigned int legs() override { return 2u; }
+};
+
+class tarantula : public spider 
+{
+public:
+	const wchar_t* c_str() override { return L"tarantula"; }
+	const unsigned int legs() override { return 8u; }
+};
+
+class leg_counter 
+{
+private:
+	unsigned int number_of_legs;
+public:
+	leg_counter();
+	~leg_counter();
+	animal& add_animal(animal& a);
+	unsigned int legs();
+};
+
+animal& animal_factory(int id);

exercise/01/animals.vcxproj.user

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup />
+</Project>

exercise/01/test.cpp

@@ -47,5 +47,4 @@ TEST_CLASS(test_animal_hierarchy)
 		lc.add_animal(animal_factory(2));
 		Assert::AreEqual(4u, lc.legs());
 	}
-
-};
+};