Java 代码,双击复制代码 package com.entor.hw;
import java.util.Scanner;
public class HW2 {
public static void main(String[] args) {
System.out.println("请输入圆的半径:");
Scanner sc = new Scanner(System.in);
double r = sc.nextDouble();
double pi = 3.14;
System.out.println("圆的周长:" +2*pi*r);
System.out.println("圆的面积:" +pi*r*r);
}
// float,double精度问题,如输入半径5,圆的周长打印为:31.400000000000002
// BigDecimal
}
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