From 8db35798bbc96be56b683eda8c65cab9e3c8867b Mon Sep 17 00:00:00 2001
From: Chengwuyi <3394813085@qq.com>
Date: Sat, 30 May 2026 22:10:47 +0800
Subject: [PATCH] =?UTF-8?q?=E4=B8=8A=E4=BC=A0=E6=96=87=E4=BB=B6=E8=87=B3?=
 =?UTF-8?q?=20'w4'?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 w4/Circle.java    | 14 ++++++++++++++
 w4/Main.java      | 21 +++++++++++++++++++++
 w4/Rectangle.java | 17 +++++++++++++++++
 w4/Shape.java     |  9 +++++++++
 w4/ShapeUtil.java | 21 +++++++++++++++++++++
 5 files changed, 82 insertions(+)
 create mode 100644 w4/Circle.java
 create mode 100644 w4/Main.java
 create mode 100644 w4/Rectangle.java
 create mode 100644 w4/Shape.java
 create mode 100644 w4/ShapeUtil.java

diff --git a/w4/Circle.java b/w4/Circle.java
new file mode 100644
index 0000000..8ecde8c
--- /dev/null
+++ b/w4/Circle.java
@@ -0,0 +1,14 @@
+public class Circle extends Shape {
+    private double radius;
+
+    public Circle(double radius) {
+        this.radius = radius;
+    }
+
+    public double getRadius() { return radius; }
+
+    @Override
+    public double getArea() {
+        return Math.PI * radius * radius;
+    }
+}
diff --git a/w4/Main.java b/w4/Main.java
new file mode 100644
index 0000000..d61c99e
--- /dev/null
+++ b/w4/Main.java
@@ -0,0 +1,21 @@
+public class Main {
+    public static void main(String[] args) {
+        // 创建图形对象
+        Shape circle    = new Circle(5.0);
+        Shape rectangle = new Rectangle(4.0, 6.0);
+        Shape triangle  = new Triangle(3.0, 8.0);
+
+        // 存入数组，统一处理（多态）
+        Shape[] shapes = { circle, rectangle, triangle };
+
+        System.out.println("===== 图形面积计算器 =====");
+        for (Shape s : shapes) {
+            ShapeUtil.printArea(s);
+        }
+
+        System.out.println();
+        Shape largest = ShapeUtil.findLargest(shapes);
+        System.out.println("面积最大的图形是：" + largest.getName()
+                           + "（面积 = " + String.format("%.2f", largest.getArea()) + "）");
+    }
+}
diff --git a/w4/Rectangle.java b/w4/Rectangle.java
new file mode 100644
index 0000000..12a9e51
--- /dev/null
+++ b/w4/Rectangle.java
@@ -0,0 +1,17 @@
+public class Rectangle extends Shape {
+    private double width;
+    private double height;
+
+    public Rectangle(double width, double height) {
+        this.width = width;
+        this.height = height;
+    }
+
+    public double getWidth()  { return width; }
+    public double getHeight() { return height; }
+
+    @Override
+    public double getArea() {
+        return width * height;
+    }
+}
diff --git a/w4/Shape.java b/w4/Shape.java
new file mode 100644
index 0000000..843d31b
--- /dev/null
+++ b/w4/Shape.java
@@ -0,0 +1,9 @@
+public abstract class Shape {
+    // 抽象方法：计算面积，子类必须实现
+    public abstract double getArea();
+
+    // 通用方法：返回图形名称（子类可重写）
+    public String getName() {
+        return this.getClass().getSimpleName();
+    }
+}
diff --git a/w4/ShapeUtil.java b/w4/ShapeUtil.java
new file mode 100644
index 0000000..d4f7f46
--- /dev/null
+++ b/w4/ShapeUtil.java
@@ -0,0 +1,21 @@
+public class ShapeUtil {
+    /**
+     * 统一打印任意图形的面积（多态调用）
+     */
+    public static void printArea(Shape shape) {
+        System.out.printf("%s 的面积为：%.2f%n", shape.getName(), shape.getArea());
+    }
+
+    /**
+     * 找出面积最大的图形
+     */
+    public static Shape findLargest(Shape[] shapes) {
+        Shape largest = shapes[0];
+        for (Shape s : shapes) {
+            if (s.getArea() > largest.getArea()) {
+                largest = s;
+            }
+        }
+        return largest;
+    }
+}