import java.util.Scanner;
class Yuan
{
Float r;
public void input()
{
Scanner scann=new Scanner(System.in);
System.out.println("请输入半径:");
r=scann.nextFloat();
}
public void yuan()
{
System.out.println("半径=:"+r);
System.out.println("周长=:"+2*Math.PI*r);
}
}
class Test
{
public static void main(String[] args)
{
Yuan yuan=new Yuan();
Yuan.input();
Yuan.yuan();
}
}
运行结果:
请输入半径:
2
半径=:2.0
周长=:12.566370614359172