4-3抽象类课后疑问路过的大侠给看看哪里不对的谢谢
来源：10-3 Java 中的抽象类
ART原艺美学
2017-03-08 16:56
父类
package imooc02;
public abstract class Shape {
public abstract void Perimeter();
public abstract void Area();
}
子类01
package imooc02;
public class Rectangle extends Shape {
@Override
public void Perimeter() {
// TODO Auto-generated method stub
double a;
double b;
double c;
double c= (a+b)*(a+b);
System.out.println("长方形的周长为"+c);
}
@Override
public void Area(){
// TODO Auto-generated method stub
double a ;
double b;
double s;
double s= a*b;
System.out.println("长方形的的面积为"+s);
}
}
子类02
package imooc02;
public class Circle extends Shape {
@Override
public void Perimeter(){
// TODO Auto-generated method stub
double π;
double d;
private double c ;
private double c= π*d;
System.out.println("圆的周长是："+c);
}
@Override
public void Area(){
// TODO Auto-generated method stub
double π;
double d;
double s;
double s= π*((d/2)*(d/2));
System.out.println("圆的面积是:"+s);
}
}
测试类
package imooc02;
public class Test {
public static void main(String[] args) {
Shape a1=new Rectangle();
a1.Perimeter();
a1.Area();
Shape a2=new Circle();
a2.Perimeter();
a2.Area();
}
}
写回答
关注
3回答
-
- 蓝_尘
- 2017-03-08 17:55:57
将double π 定义为常量 final PI=3.14;试试
-
- kirito_yes
- 2017-03-18 13:17:47
既然一个类里面两个方法的变量都一样的话，可以直接拿出来啊，在类里定义写一遍就好了。
-
- ART原艺美学
- 2017-03-08 18:44:29
父类 package imooc02; public abstract class Shape { public abstract void Perimeter(); public abstract void Area(); } 子类 package imooc02; public class Rectangle extends Shape { @Override public void Perimeter() { // TODO Auto-generated method stub double a=10.0; double b=10.0; double c; c= (a+b)*2; System.out.println("长方形的周长为"+c); } @Override public void Area(){ // TODO Auto-generated method stub double a=10.0 ; double b=10.0; double s; s= a*b; System.out.println("长方形的的面积为"+s); } } 子类02 package imooc02; public class Circle extends Shape { @Override public void Perimeter(){ // TODO Auto-generated method stub final double PI=3.14; double d=9.0; double c ; c= PI*d; System.out.println("圆的周长是："+c); } @Override public void Area(){ // TODO Auto-generated method stub final double PI=3.14;; double d=9.0; double s; s= PI*(d/2); System.out.println("圆的面积是:"+s); } } 测试类 package imooc02; public class Test { public static void main(String[] args) { Shape a1=new Rectangle(); a1.Perimeter(); a1.Area(); Shape a2=new Circle(); a2.Perimeter(); a2.Area(); } } 长方形的周长为40.0 长方形的的面积为100.0 圆的周长是：28.26 圆的面积是:14.13
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