题目:
代码:
1.矩形类Rect:
public class Rect {
private double chang;
private double kuan;
public Rect() {
}
public Rect(double chang, double kuan) {
this.chang = chang;
this.kuan = kuan;
}
public double getChang() {
return chang;
}
public void setChang(double chang) {
this.chang = chang;
}
public double getKuan