为什么这里的F不能被调用？

Question

class Area{

double F(double f){

return 3.14*f*f;

}

double G(double X,double Y){

return X+Y;

}

}

class Circle extends Area{

double F(double f){

return 2*3.14*f;

}

}

public class TestArea {

double lenght,sum;

Circle yuan=new Circle();

//yuan.F(5.0);

}

Answer 1

在妹涵数里面new, 然后调用