diff --git a/lectures/25_inheritance/students/student_test2.cpp b/lectures/25_inheritance/students/student_test2.cpp
index f5ca964..6b7c327 100644
--- a/lectures/25_inheritance/students/student_test2.cpp
+++ b/lectures/25_inheritance/students/student_test2.cpp
@@ -21,6 +21,12 @@ public:
 
 class Student : public Human {
 public:
+    /* in C++, when a derived class inherits from a base class,
+    * the base class's constructor must be called to initialize its members.
+    * This is because the base class may contain private or protected members
+    * that are not directly accessible by the derived class.
+    * Therefore, the derived class relies on the base class's constructor to properly initialize these members. */
+
     Student(std::string n, int a, int s) : Human(n, a, s) {}
 };
 
diff --git a/lectures/25_inheritance/students/student_test4.cpp b/lectures/25_inheritance/students/student_test4.cpp
new file mode 100644
index 0000000..f5d9f71
--- /dev/null
+++ b/lectures/25_inheritance/students/student_test4.cpp
@@ -0,0 +1,63 @@
+#include <iostream>
+#include <string>
+
+class Human {
+// change this to protect so that these variables can be accessed by the derived class.
+protected:
+    std::string name;
+    int age;
+    int sleep_hours;
+
+public:
+    Human(std::string n, int a, int s) : name(n), age(a), sleep_hours(s) {}
+    ~Human(){
+	    std::cout << "Human Destructor" << std::endl;
+    }
+
+    void introduce() {
+        std::cout << "Hello, I am " << name << ", and I am " << age << " years old.\n";
+    }
+
+    void sleep() {
+        std::cout << name << " is " << age << " years old who sleeps " << sleep_hours << " hours a night.\n";
+    }
+};
+
+class Student : public Human {
+public:
+    Student(std::string n, int a, int s) : Human(n, a, s) {}
+    ~Student(){
+	    std::cout << "Student Destructor" << std::endl;
+    }
+    
+    void introduce() {
+        std::cout << "Hello, I am " << name << ", and I am " << age << " years old. I’m majoring in 'How did I get here?' with a minor in 'It sounded easier when I signed up.'\n";
+    }
+
+    void sleep() {
+        std::cout << name << " is a college student who sleeps " << sleep_hours << " hours a night, and sleep 2 hours during boring lectures.\n";
+    }
+};
+
+int main() {
+    // Creating instances of each class with member variables
+    Human h("Alice", 30, 8);
+    Student s("Bob", 20, 5);
+
+    // Introducing Humans
+    std::cout << "--- Human introducing ---\n";
+    h.introduce();  // Output: Hello, I am Alice, and I am 30 years old.
+    
+    std::cout << "--- Student introducing ---\n";
+    s.introduce();  // Output: I am a student. My name is Bob, and I am 20 years old.
+
+    // Showing sleep behavior
+    std::cout << "--- Human sleep ---\n";
+    h.sleep();  // Output: Alice is 30 years old and sleeps 8 hours a night.
+
+    std::cout << "--- Student sleep ---\n";
+    s.sleep();  // Output: Bob is a student, and they sleep 5 hours a night.
+
+    return 0;
+}
+