adding info about memory size for virtual functions

lectures/26_inheritance_II/virtual3.cpp

@@ -0,0 +1,37 @@
+#include <iostream>
+
+class Human {
+};
+
+class Student {
+	int age;
+};
+
+class CollegeStudent {
+	int age;
+	void print(){
+		std::cout << "I am a college student." << std::endl;
+	}
+};
+
+class CSStudent {
+	int age;
+	virtual void print(){
+		std::cout << "I am a CS student." << std::endl;
+	}
+	virtual void print2(){
+		std::cout << "I am still a CS student." << std::endl;
+	}
+	virtual void print3(){
+		std::cout << "I am still a CS student." << std::endl;
+	}
+};
+
+int main(){
+	CSStudent cs;
+	std::cout << "memory size of Human class is: " << sizeof(Human) << std::endl;
+	std::cout << "memory size of Student class is: " << sizeof(Student) << std::endl;
+	std::cout << "memory size of College Student class is: " << sizeof(CollegeStudent) << std::endl;
+	std::cout << "memory size of CS Student class is: " << sizeof(CSStudent) << std::endl;
+	return 0;
+}