diff --git a/OOP/02/Exercise01.cpp b/OOP/02/Exercise01.cpp
new file mode 100644
index 0000000..55e09df
--- /dev/null
+++ b/OOP/02/Exercise01.cpp
@@ -0,0 +1,40 @@
+#include <iostream>
+
+class Student {
+private:
+    int ID, grade;
+
+public:
+    Student() {
+        this->ID = 0;
+        this->grade = 0;
+    };
+
+    Student(int newID, int newGrade) : ID(newID), grade(newGrade){};
+
+    void display();
+
+    void set(int, int);
+};
+
+void Student::display() {
+    std::cout << "ID: " << this->ID << ", Grade: " << this->grade << std::endl;
+}
+
+void Student::set(int newID, int newGrade) {
+    this->ID = newID;
+    this->grade = newGrade;
+}
+
+int main() {
+    Student stu[5];
+    stu[0].set(21394,89);
+    stu[1].set(2394888, 100);
+    stu[2].set(299, 70);
+    stu[3].set(3999, 10);
+    stu[4].set(4999, 60);
+    stu[0].display();
+    stu[2].display();
+    stu[4].display();
+    return 0;
+}
\ No newline at end of file
diff --git a/OOP/02/Optional02.cpp b/OOP/02/Optional02.cpp
new file mode 100644
index 0000000..0e5d374
--- /dev/null
+++ b/OOP/02/Optional02.cpp
@@ -0,0 +1,47 @@
+#include <iostream>
+#include <stdlib.h>
+
+class Strings {
+public:
+    Strings(char *s);
+    ~Strings();
+    void Print();
+    void Set(char *s);
+
+private:
+    int length;
+    char *str;
+};
+
+Strings::Strings(char *s) {
+    length = strlen(s);
+    str = (char *)malloc(length + 1);
+    strcpy(str, s);
+}
+
+Strings::~Strings() {
+    free(str);
+}
+
+void Strings::Print() {
+    std::cout << str << std::endl;
+}
+
+void Strings::Set(char *s) {
+    free(str);
+    length = strlen(s);
+    str = (char *)malloc(length + 1);
+    strcpy(str, s);
+}
+
+int main() {
+    Strings* str1 = new Strings("didig");
+    Strings* str2 = new Strings("dirir");
+
+    str1->Print();
+    str2->Print();
+    str1->Set("ifirk");
+    str1->Print();
+
+    return 0;
+}
\ No newline at end of file
diff --git a/OOP/EmployeeAdmin/employee.h b/OOP/EmployeeAdmin/employee.h
new file mode 100644
index 0000000..5305538
--- /dev/null
+++ b/OOP/EmployeeAdmin/employee.h
@@ -0,0 +1,15 @@
+class Employee {
+private:
+    int individualEmpNo;
+    int grade;
+    int accumPay;
+
+public:
+    Employee();
+    Employee(int no, int newGrade, int newAccumPay);
+    ~Employee();
+    void printInfo();
+    void setEmpNo(int);
+    void setGrade(int);
+    void setAccumPay(int);
+};
\ No newline at end of file
diff --git a/OOP/EmployeeAdmin/main.cpp b/OOP/EmployeeAdmin/main.cpp
new file mode 100644
index 0000000..b10488d
--- /dev/null
+++ b/OOP/EmployeeAdmin/main.cpp
@@ -0,0 +1,50 @@
+#include <iostream>
+#include "employee.h"
+
+Employee::Employee() {
+    this->individualEmpNo = 0;
+    this->grade = 0;
+    this->accumPay = 0;
+}
+
+Employee::Employee(int no, int newGrade, int newAccumPay) {
+    this->individualEmpNo = no;
+    this->grade = newGrade;
+    this->accumPay = newAccumPay;
+}
+
+Employee::~Employee() {
+    std::cout << "欢迎使用，再见" << std::endl;
+}
+
+void Employee::printInfo() {
+    std::cout << "Employee No. " << this->individualEmpNo << ": grade " << this->grade << ", accumPay: " << this->accumPay << std::endl;
+}
+
+void Employee::setEmpNo(int newNo) {
+    this->individualEmpNo = newNo;
+}
+
+void Employee::setGrade(int newGrade) {
+    this->grade = newGrade;
+}
+
+void Employee::setAccumPay(int newAccumPay) {
+    this->accumPay = newAccumPay;
+}
+
+int main() {
+    Employee* staff[4];
+    staff[0] = new Employee();
+    staff[1] = new Employee(11343, 2, 2000);
+    staff[2] = new Employee(199, 1, 4000);
+    staff[3] = new Employee(59949, 4, 400);
+
+    for (int i = 0; i < 4; i++) {
+        staff[i]->printInfo();
+    }
+
+    delete staff[3];
+
+    return 0;
+}
\ No newline at end of file