chapter 4

src/chapter4/Example01.java

@@ -0,0 +1,44 @@
+package chapter4;
+
+class Animal {
+    private String name;
+    private int age;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+}
+
+// 定义 Dog 类继承 Animal 类
+class Dog extends Animal {
+    private String color;
+
+    public String getColor() {
+        return color;
+    }
+
+    public void setColor(String color) {
+        this.color = color;
+    }
+}
+
+public class Example01 {
+    public static void main(String[] args) {
+        Dog dog = new Dog();
+        dog.setName("牧羊犬");
+        dog.setAge(3);
+        System.out.println("名称：" + dog.getName() + "，年龄：" + dog.getAge());
+    }
+}