上传文件至 'W4周梓浩202506050319'

W4周梓浩202506050319/Shape.java

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+package Shape;
+
+abstract public class Shape {
+    abstract double getArea();
+}
+class Circle extends Shape{
+    private double r;
+    public Circle(double r){
+        this.r=r;
+    }
+    @Override
+    double getArea(){
+        return Math.PI*r*r;
+    }
+}
+
+class Rectangle extends Shape{
+    private double chang;
+    private double kuan;
+    public Rectangle(double chang,double kuan){
+        this.chang=chang;
+        this.kuan=kuan;
+    }
+    @Override
+    double getArea(){
+        return chang*kuan;
+    }
+}
+
+class Triangle extends Shape{
+    private double di;
+    private double height;
+    public Triangle(double di,double height){
+        this.di=di;
+        this.height=height;
+    }
+    @Override
+    double getArea(){
+        return 0.5*di*height;
+    }
+}
+
+class ShapeUtil{
+    public static void printArea(Shape shape){
+        System.out.println("面积是"+shape.getArea());
+    }
+}

W4周梓浩202506050319/ShapeTest.java

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+package Shape;
+
+public class ShapeTest {
+    public static void main(String[] args){
+        System.out.println("--测试三个类--");
+        //circle
+        Circle round=new Circle(5);
+        Rectangle b=new Rectangle(4,7);
+        Triangle c=new Triangle(8,4);
+        ShapeUtil.printArea(round);
+        ShapeUtil.printArea(b);
+        ShapeUtil.printArea(c);
+    }
+}