子类:public class ShapeCircle extends Shape

{

protected double r;

public ShapeCircle()

{

setside(0.0);

}

public ShapeCircle(double r)

{

setside(r);

}

public void setside(double r)

{

this.r=r;

}

public double perimeter()

{

return Math.PI*2*r;

}

public String getType()

{

return "Circle";

}

}

父类:

import ShapeCircle;

import Shape;

public class Myshape

{

private static ShapeCircle sc=new ShapeCircle(4);

private static Shape shapej=new ShapeCircle(5);

public static void main(String args[])

{

System.out.println(sc.getType()+","+sc.perimeter());

}

shapej=sc;

System.out.println(shape.getType()+","+shape.perimeter());

}

当编译到shapej=sc总报错.为什么,请高手指教.

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public static void main(String args[])

{

System.out.println(sc.getType()+","+sc.perimeter());

shapej=sc;

System.out.println(shapej.getType()+","+shapej.perimeter());

}

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你的语句不能直接写在类里，如果写的话可写为

static {

shapej=sc;

System.out.println(shape.getType()+","+shape.perimeter());

}

或者写成：　karma(无为)的方式

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I guess dongjh forgot to put } after

System.out.println(shape.getType()+","+shape.perimeter());