java第八周练习题8.1

题目：

定义一个矩形类，有默认构造函数，和带有width,height参数的构造函数，在类内求出矩形的面积和周长。用带有参数的构造函数初始化width和height。

<pre name="code" class="java">public class aa {static class Rectangle {double width = 1;double height = 1;Rectangle() {}Rectangle(double w, double h) {width = w;height = h;}double getArea() {return width * height;}double getPerimeter() {return 2 * (width + height);}}public static void main(String[] args) {// TODO Auto-generated method stubRectangle r=new Rectangle(4.0,40.0);System.out.println(r.width+" "+r.height);System.out.println(r.getArea()+" "+r.getPerimeter());r=new Rectangle(3.5,35.9);System.out.println(r.width+" "+r.height);System.out.println(r.getArea()+" "+r.getPerimeter());}}

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