上传文件至 'w5'

w5/ShapeUtil.java

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+abstract class Shape {
+    public abstract double getArea();
+}
+class Circle extends Shape {
+    private double radius;
+    public Circle(double radius) {
+        this.radius = radius;
+    }
+    @Override
+    public double getArea() {
+        return Math.PI * radius * radius;
+    }
+}
+class Rectangle extends Shape {
+    private double width;
+    private double height;
+    public Rectangle(double width, double height) {
+        this.width = width;
+        this.height = height;
+    }
+    @Override
+    public double getArea() {
+        return width * height;
+    }
+}
+class Triangle extends Shape {
+    private double base;
+    private double height;
+    public Triangle(double base, double height) {
+        this.base = base;
+        this.height = height;
+    }
+    @Override
+    public double getArea() {
+        return 0.5 * base * height;
+    }
+}
+public class ShapeUtil {
+    public static void printArea(Shape shape) {
+        System.out.println("面积：" + shape.getArea());
+    }
+    public static void main(String[] args) {
+        Shape circle = new Circle(6);
+        Shape rectangle = new Rectangle(9, 10);
+        Shape triangle = new Triangle(5, 10);
+        printArea(circle);
+        printArea(rectangle);
+        printArea(triangle);
+    }
+}
+        

w5/shape_class_diagram.puml

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+@startuml
+' 形状类图
+
+' 抽象类 Shape
+abstract class Shape {
+    + getArea(): double
+}
+
+' Circle 类
+class Circle {
+    - radius: double
+    + Circle(radius: double)
+    + getArea(): double
+}
+
+' Rectangle 类
+class Rectangle {
+    - width: double
+    - height: double
+    + Rectangle(width: double, height: double)
+    + getArea(): double
+}
+
+' Triangle 类
+class Triangle {
+    - base: double
+    - height: double
+    + Triangle(base: double, height: double)
+    + getArea(): double
+}
+
+' ShapeUtil 工具类
+class ShapeUtil {
+    + printArea(shape: Shape): void
+    + main(args: String[]): void
+}
+
+' 继承关系
+Shape <|-- Circle
+Shape <|-- Rectangle
+Shape <|-- Triangle
+
+' 使用关系
+ShapeUtil --> Shape
+
+@enduml