commit a7ac3da214ff891433e9891e90d2b7a6d80e0e76
Author: 故春 <3481369387@qq.com>
Date:   Fri Mar 27 22:26:02 2026 +0800

    添加W3

diff --git a/W3/Circle.java b/W3/Circle.java
new file mode 100644
index 0000000..17338cb
--- /dev/null
+++ b/W3/Circle.java
@@ -0,0 +1,12 @@
+public class Circle extends Shape {
+    private double radius;
+
+    public Circle(double radius) {
+        this.radius = radius;
+    }
+
+    @Override
+    public double getArea() {
+        return Math.PI * radius * radius;
+    }
+}
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diff --git a/W3/QQ20260327-221432.png b/W3/QQ20260327-221432.png
new file mode 100644
index 0000000..3adcd69
Binary files /dev/null and b/W3/QQ20260327-221432.png differ
diff --git a/W3/Rectangle.java b/W3/Rectangle.java
new file mode 100644
index 0000000..faabd17
--- /dev/null
+++ b/W3/Rectangle.java
@@ -0,0 +1,14 @@
+public 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;
+    }
+}
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diff --git a/W3/Shape.java b/W3/Shape.java
new file mode 100644
index 0000000..390e266
--- /dev/null
+++ b/W3/Shape.java
@@ -0,0 +1,4 @@
+public abstract class Shape {
+    // 抽象方法：计算图形面积
+    public abstract double getArea();
+}
diff --git a/W3/ShapeUtil.java b/W3/ShapeUtil.java
new file mode 100644
index 0000000..cbef7bc
--- /dev/null
+++ b/W3/ShapeUtil.java
@@ -0,0 +1,9 @@
+public class ShapeUtil {
+    public static void printArea(Shape shape) {
+        if (shape == null) {
+            System.out.println("图形对象不能为空！");
+            return;
+        }
+        System.out.printf("图形面积为：%.2f%n", shape.getArea());
+    }
+}
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diff --git a/W3/Test.java b/W3/Test.java
new file mode 100644
index 0000000..9ce9940
--- /dev/null
+++ b/W3/Test.java
@@ -0,0 +1,18 @@
+public class Test {
+    public static void main(String[] args) {
+        // 创建不同图形对象
+        Shape circle = new Circle(3);
+        Shape rect = new Rectangle(4, 5);
+        Shape triangle = new Triangle(3, 4, 5);
+
+        // 统一调用工具类打印面积
+        System.out.println("圆形：");
+        ShapeUtil.printArea(circle);
+
+        System.out.println("矩形：");
+        ShapeUtil.printArea(rect);
+
+        System.out.println("三角形：");
+        ShapeUtil.printArea(triangle);
+    }
+}
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diff --git a/W3/Triangle.java b/W3/Triangle.java
new file mode 100644
index 0000000..9f9f6a7
--- /dev/null
+++ b/W3/Triangle.java
@@ -0,0 +1,15 @@
+public class Triangle extends Shape {
+    private double a, b, c;
+
+    public Triangle(double a, double b, double c) {
+        this.a = a;
+        this.b = b;
+        this.c = c;
+    }
+
+    @Override
+    public double getArea() {
+        double p = (a + b + c) / 2;
+        return Math.sqrt(p * (p - a) * (p - b) * (p - c));
+    }
+}
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diff --git a/W3/W3.txt b/W3/W3.txt
new file mode 100644
index 0000000..e69de29
diff --git a/desktop.ini b/desktop.ini
new file mode 100644
index 0000000..1511bb0
--- /dev/null
+++ b/desktop.ini
@@ -0,0 +1,2 @@
+[LocalizedFileNames]
+QQ20260327-221432.png=@QQ20260327-221432.png,0