add intro

CPlusPlus/intro/ClassA.h

@@ -0,0 +1,20 @@
+#pragma once
+
+class ClassA
+{
+	// private
+
+public:
+	// public
+	ClassA(); // default constructor
+	ClassA(const ClassA& other); // copy constructor
+	~ClassA(); // destructor
+
+protected:
+	// protected
+
+private:
+	// private
+	int* _pNumber = nullptr;
+};
+