diff --git a/实验3/README.md b/实验3/README.md
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+## Getting Started
+
+Welcome to the VS Code Java world. Here is a guideline to help you get started to write Java code in Visual Studio Code.
+
+## Folder Structure
+
+The workspace contains two folders by default, where:
+
+- `src`: the folder to maintain sources
+- `lib`: the folder to maintain dependencies
+
+Meanwhile, the compiled output files will be generated in the `bin` folder by default.
+
+> If you want to customize the folder structure, open `.vscode/settings.json` and update the related settings there.
+
+## Dependency Management
+
+The `JAVA PROJECTS` view allows you to manage your dependencies. More details can be found [here](https://github.com/microsoft/vscode-java-dependency#manage-dependencies).
diff --git a/实验3/src/test1/Student.java b/实验3/src/test1/Student.java
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+++ b/实验3/src/test1/Student.java
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+//Student.java
+package test1;
+
+public class Student {
+    int id;
+    int age;
+    int grade;
+
+    public void study() {
+        System.err.println("学号为" + id + "的学生正在学习");
+    }
+
+    public void examination() {
+        System.err.println(id + "年级正在考试");
+    }
+
+    public void tell() {
+        System.out.print("正在讲话的是一个" + age + "岁的学生");
+    }
+
+}
diff --git a/实验3/src/test1/test.java b/实验3/src/test1/test.java
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+++ b/实验3/src/test1/test.java
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+//test.java
+package test1;
+
+public class test {
+    public static void main(String[] args) {
+        Student s1 = new Student();
+        s1.id = 001;
+        s1.age = 18;
+        s1.grade = 1;
+        s1.study();
+        s1.examination();
+        s1.tell();
+    }
+}
diff --git a/实验3/src/test2/Circle.java b/实验3/src/test2/Circle.java
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+++ b/实验3/src/test2/Circle.java
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+//Circle.java
+package test2;
+
+public class Circle {
+    double radius;
+    double area;
+
+    public void set(double radius) {
+        this.radius = radius;
+    }
+
+    public void disaplay() {
+        area = radius * radius * 3.14;
+        System.err.println("This circle's radius is " + radius + ", area is " + area);
+    }
+}
diff --git a/实验3/src/test2/Cone.java b/实验3/src/test2/Cone.java
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+++ b/实验3/src/test2/Cone.java
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+//Cone.java
+package test2;
+
+public class Cone {
+    double buttom;
+    double height;
+
+    public void set(double buttom, double height) {
+        this.buttom = buttom;
+        this.height = height;
+    }
+
+    public Cone() {
+    }
+
+    public void disaplay() {
+        System.out.println(
+                "This cone's buttom area is " + buttom + ", height is " + height + ", volume is "
+                        + buttom * height / 3);
+    }
+}
diff --git a/实验3/src/test2/test.java b/实验3/src/test2/test.java
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+++ b/实验3/src/test2/test.java
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+//test.java
+package test2;
+
+public class test {
+
+    public static void main(String[] args) {
+        Circle r1 = new Circle();
+        r1.set(3);
+        r1.disaplay();
+        Cone c1 = new Cone();
+        c1.set(28.26, 5);
+        c1.disaplay();
+    }
+}
diff --git a/实验3/src/test3/Student.java b/实验3/src/test3/Student.java
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+++ b/实验3/src/test3/Student.java
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+//Student.java
+package test3;
+
+public class Student {
+    private int age;
+    private String sex;
+
+    // setters
+    public void setAge(int age) {
+        if (age >= 0 & age <= 120) {
+            this.age = age;
+        } else {
+            this.age = 18;
+        }
+    }
+
+    public void setSex(String sex) {
+        if ("男".equals(sex) || "女".equals(sex)) {
+            this.sex = sex;
+        } else {
+            this.sex = "保密";
+        }
+    }
+
+    // getters
+    public int getAge() {
+        return age;
+    }
+
+    public String getSex() {
+        return sex;
+    }
+}
diff --git a/实验3/src/test3/test.java b/实验3/src/test3/test.java
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+++ b/实验3/src/test3/test.java
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+//test.java
+package test3;
+
+import java.util.Scanner;
+
+public class test {
+    public static void main(String[] args) {
+        Scanner input = new Scanner(System.in);
+        Student s1 = new Student();
+        s1.setAge(input.nextInt());
+        s1.setSex(input.next());
+        System.out.println("This student's age is " + s1.getAge() + ", gender is " + s1.getSex());
+    }
+}
diff --git a/实验3/src/test4/Yard.java b/实验3/src/test4/Yard.java
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+++ b/实验3/src/test4/Yard.java
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+//Yard.java
+package test4;
+
+public class Yard {
+    double length;
+    double width;
+
+    public Yard(double length, double width) {
+        this.length = length;
+        this.width = width;
+    }
+
+    public double getPerimeter() {
+        return (length + width) * 2;
+    }
+
+    public double getAcreage() {
+        return length * width;
+    }
+}
diff --git a/实验3/src/test4/test.java b/实验3/src/test4/test.java
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+++ b/实验3/src/test4/test.java
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+//test.java
+package test4;
+
+import java.util.Scanner;
+
+public class test {
+    public static void main(String[] args) {
+        Scanner input = new Scanner(System.in);
+        Yard y1 = new Yard(input.nextDouble(), input.nextDouble());
+        System.err.println(y1.getPerimeter()+" "+y1.getAcreage());
+    }
+}
diff --git a/实验3/src/test5/Employee.java b/实验3/src/test5/Employee.java
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+++ b/实验3/src/test5/Employee.java
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+//Employee.java
+package test5;
+
+public class Employee {
+    String name;
+    int age;
+    String dept;
+    static String company;
+
+    public void showInfos() {
+        System.out.println("name\t" + name);
+        System.out.println("age\t" + age);
+        System.out.println("dept\t" + dept);
+        System.out.println("company\t" + company);
+        System.out.println();
+    }
+
+    public static int compareAge(int age1, int age2) {
+        if (age1 > age2) {
+            return age1;
+        } else {
+            return age2;
+        }
+    }
+}
diff --git a/实验3/src/test5/test.java b/实验3/src/test5/test.java
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+++ b/实验3/src/test5/test.java
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+//test.java
+package test5;
+
+public class test {
+    public static void main(String[] args) {
+        Employee e1 = new Employee();
+        e1.name = "Jack";
+        e1.age = 30;
+        e1.dept = "Software";
+        Employee.company = "XJIT.inc";
+        e1.showInfos();
+        Employee e2 = new Employee();
+        e2.name = "Mike";
+        e2.age = 45;
+        e2.dept = "Hardware";
+        e2.showInfos();
+        System.out.println("2个人中最大年龄是" + Employee.compareAge(e1.age, e2.age) + "岁。");
+    }
+}
diff --git a/实验3/实验3/.vscode/settings.json b/实验3/实验3/.vscode/settings.json
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+++ b/实验3/实验3/.vscode/settings.json
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+{
+    "java.project.sourcePaths": ["src"],
+    "java.project.outputPath": "bin",
+    "java.project.referencedLibraries": [
+        "lib/**/*.jar"
+    ]
+}