>>347
public abstract class Main {
　public static void main(String[] args) {
　　Main main = new Sub();
　　main.height = 1.70;
　　main.weight = 70.0;
　　System.out.printf("%.2f%n", main.calc());
　}

　double weight;
　double height;

　abstract double calc();
}

class Sub extends Main {
　@Override
　double calc() {
　　return (double) weight / (height * height);
　}
}