java计算圆直径，周长，面积
import java.util.Scanner;
public class CircleCalculator {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("banjingshi ");
double radius = scanner.nextDouble();
double area = Math.PI * Math.pow(radius, 2);
double circumference = 2 * Math.PI * radius;
double diameter = 2 * radius;
System.out.println("mianji " + area);
System.out.println("zhouchang " + circumference);
System.out.println("zhijing " + diameter);
}
}