diff --git a/ex5-library/src/Employee.cpp b/ex5-library/src/Employee.cpp
new file mode 100644
index 0000000..f1a7707
--- /dev/null
+++ b/ex5-library/src/Employee.cpp
@@ -0,0 +1,31 @@
+/*
+ * Employee.cpp
+ *
+ *  Created on: Nov 15, 2024
+ *      Author: ahypki
+ */
+
+#include "Employee.h"
+
+namespace lib {
+
+Employee::Employee() {
+	// TODO Auto-generated constructor stub
+
+}
+
+Employee::Employee(int pesel) {
+	setPesel(pesel);
+}
+
+Employee::~Employee() {
+	// TODO Auto-generated destructor stub
+}
+
+bool Employee::validate() {
+	if (getPesel() < 1000000)
+		return false;
+	return true;
+}
+
+} /* namespace lib */
diff --git a/ex5-library/src/Employee.h b/ex5-library/src/Employee.h
new file mode 100644
index 0000000..b707eb9
--- /dev/null
+++ b/ex5-library/src/Employee.h
@@ -0,0 +1,26 @@
+/*
+ * Employee.h
+ *
+ *  Created on: Nov 15, 2024
+ *      Author: ahypki
+ */
+
+#ifndef EMPLOYEE_H_
+#define EMPLOYEE_H_
+
+#include "Human.h"
+
+namespace lib {
+
+class Employee : public Human {
+public:
+	Employee();
+	Employee(int pesel);
+	~Employee();
+
+	bool validate();
+};
+
+} /* namespace lib */
+
+#endif /* EMPLOYEE_H_ */
diff --git a/ex5-library/src/Human.cpp b/ex5-library/src/Human.cpp
new file mode 100644
index 0000000..7bf448e
--- /dev/null
+++ b/ex5-library/src/Human.cpp
@@ -0,0 +1,45 @@
+/*
+ * Human.cpp
+ *
+ *  Created on: Nov 15, 2024
+ *      Author: ahypki
+ */
+
+#include "Human.h"
+
+namespace lib {
+
+Human::Human() {
+	// TODO Auto-generated constructor stub
+
+}
+
+Human::~Human() {
+	// TODO Auto-generated destructor stub
+}
+
+long Human::getPesel() {
+	return pesel;
+}
+
+void Human::setPesel(long pesel) {
+	this->pesel = pesel;
+}
+
+string Human::getFirstname() {
+	return this->firstname;
+}
+
+void Human::setFirstname(string firstname) {
+	this->firstname = firstname;
+}
+
+string Human::getPosition() {
+	return this->position;
+}
+
+void Human::setPosition(string position) {
+	this->position = position;
+}
+
+} /* namespace lib */
diff --git a/ex5-library/src/Human.h b/ex5-library/src/Human.h
new file mode 100644
index 0000000..d005be4
--- /dev/null
+++ b/ex5-library/src/Human.h
@@ -0,0 +1,44 @@
+/*
+ * Human.h
+ *
+ *  Created on: Nov 15, 2024
+ *      Author: ahypki
+ */
+
+#ifndef HUMAN_H_
+#define HUMAN_H_
+
+#include "iostream"
+
+namespace lib {
+
+using namespace std;
+
+class Human {
+private:
+	long pesel = 1234;
+	string firstname;
+	string lastname;
+	string position;
+protected:
+	virtual bool validate() = 0;
+public:
+	Human();
+	virtual ~Human();
+
+	long getPesel();
+	void setPesel(long pesel);
+
+	string getFirstname();
+	void setFirstname(string firstname);
+
+	string getLastname();
+	void setLastname(string lastname);
+
+	string getPosition();
+	void setPosition(string position);
+};
+
+} /* namespace lib */
+
+#endif /* HUMAN_H_ */
diff --git a/ex5-library/src/Librarian.cpp b/ex5-library/src/Librarian.cpp
new file mode 100644
index 0000000..4f99f1f
--- /dev/null
+++ b/ex5-library/src/Librarian.cpp
@@ -0,0 +1,33 @@
+/*
+ * Librarian.cpp
+ *
+ *  Created on: Nov 22, 2024
+ *      Author: ahypki
+ */
+
+#include "Librarian.h"
+
+namespace lib {
+
+Librarian::Librarian() {
+	// TODO Auto-generated constructor stub
+
+}
+
+Librarian::~Librarian() {
+	// TODO Auto-generated destructor stub
+}
+
+bool Librarian::validate() {
+	bool fromParent = Employee::validate();
+	if (fromParent == false)
+		return false;
+
+	// additional checks
+	if (getPosition().compare("librarian") != 0)
+		return false;
+
+	return true;
+}
+
+} /* namespace lib */
diff --git a/ex5-library/src/Librarian.h b/ex5-library/src/Librarian.h
new file mode 100644
index 0000000..f84fbc1
--- /dev/null
+++ b/ex5-library/src/Librarian.h
@@ -0,0 +1,25 @@
+/*
+ * Librarian.h
+ *
+ *  Created on: Nov 22, 2024
+ *      Author: ahypki
+ */
+
+#ifndef LIBRARIAN_H_
+#define LIBRARIAN_H_
+
+#include "Employee.h"
+
+namespace lib {
+
+class Librarian : public Employee {
+public:
+	Librarian();
+	virtual ~Librarian();
+
+	bool validate();
+};
+
+} /* namespace lib */
+
+#endif /* LIBRARIAN_H_ */
diff --git a/ex5-library/src/main.cpp b/ex5-library/src/main.cpp
new file mode 100644
index 0000000..44a56b0
--- /dev/null
+++ b/ex5-library/src/main.cpp
@@ -0,0 +1,24 @@
+//============================================================================
+// Name        : wmi-bioinf-library.cpp
+// Author      : 
+// Version     :
+// Copyright   : Your copyright notice
+// Description : Hello World in C++, Ansi-style
+//============================================================================
+
+#include <iostream>
+#include "Human.h"
+#include "Employee.h"
+
+using namespace std;
+
+int main() {
+	std::cout << "!!!Hello World!!!" << endl; // prints !!!Hello World!!!
+
+	lib::Employee e = lib::Employee();
+
+	if (e.validate())
+		cout << "pesel of employee" << e.getPesel();
+
+	return 0;
+}