feat:ShapeCalculator

w5/ShapeCalculator.java

@@ -0,0 +1,56 @@
+package w5;
+
+public class ShapeCalculator {
+    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;
+        }
+    }
+    class ShapeUtil {
+        public static void printArea(Shape shape) {
+            System.out.println("图形面积为：" + shape.getArea());
+        }
+    }
+    public static void main(String[] args) {
+        ShapeCalculator calculator = new ShapeCalculator();
+        Shape circle = calculator.new Circle(5);
+        Shape rectangle = calculator.new Rectangle(4,6);
+        Shape triangle = calculator.new Triangle(3,8);
+        System.out.println("====== 图形面积计算器 ======");
+        ShapeUtil.printArea(circle);
+        ShapeUtil.printArea(rectangle);
+        ShapeUtil.printArea(triangle);
+    }
+}