java方法的重载

//GraphAreaTest.java

import java.util.Scanner;
class GraphArea{
double area(float r){
return 3.14*r*r;
}
double area(float width,float height){
return width*height;
}
double area(float a,float b,float c){
float s=(a+b+c)/2;
return Math.sqrt(s*(s-a)*(s-b)*(s-c));
}
}
class GraphAreaTest{
public static void main(String[] args){
GraphArea area=new GraphArea();
System.out.println("The area of circle is "+area.area(3));
System.out.println("The area of rectangle is "+area.area(3,4));
System.out.println("The area of triangle is "+area.area(3,4,5));
}
}