抽象类：Shape
public abstract class Shape {
protected double c;
public abstract double area();
}
类Square正方形，继承抽象类
public class Square extends Shape{
public Square(double c){
this.c = c;
}
/*
* 计算正方形的面积
*/
public double area(){
return 0.0625*c*c;
}
}
类Circle 圆形，继承抽象类
public class Circle extends Shape {
public Circle(double c){
this.c = c;
}
/*
* 计算圆形面积
*/
public double area(){
return 0.0796*c*c;
}
}
测试类
public class TestShape {
public static void main(String[] args){
Shape[] shapes = new Shape[2];
shapes[0] = new Circle(4);//数组中的第一个元素为圆形。周长为4
shapes[1] = new Square(4);//数组中的第二个元素为正方形，周长为4
maxArea(shapes);
}
public static void maxArea(Shape[] shapes){
double max = shapes[0].area();
int maxIndex = 0;
for(int i = 1;i<shapes.length;i++){
double area = shapes[i].area();
if(area>max){
max = area;
maxIndex = i;
}
}
System.out.println("数组索引为："+maxIndex+"的图形的面积最大，面积为："+max);
}
}
