構造一個Circle類，該類有一個私有double變量radius存放半徑，可以通過get/set方法進行訪問。該類具有getArea和getLength兩個方法，能夠利用半徑和Math.PI計算高精度的面積和周長。輸入要求任意多個雙精度半徑，每行一個輸出要求第一行具有該半徑的圓的面積和周長，保留兩位小數第二行具有2倍于該半徑的圓的面積和周長，保留兩位小數假如輸入123應當輸出3.14 6.2812.57 12.5712.57 12.5750.27 25.1328.27 18.85113.10 37.70
2 回答
泛舟湖上清波郎朗
TA貢獻1818條經驗 獲得超3個贊
Circle.java
/**
* @Description TODO
* @Author Becolette
* @Date 2017-4-11 下午09:13:39
* @Modified By Becolette at 2017-4-11 for TODO
*/
public class Circle {
private double radius; // 半徑
public double getRadius() {
return radius;
}
public void setRadius(double radius) {
this.radius = radius;
}
public double getArea(double radius) {
return Math.PI * radius * radius;
}
public double getLength(double radius) {
return 2 * Math.PI * radius;
}
}
Test1.java
import java.text.DecimalFormat;
import java.util.Scanner;
/**
* @Description TODO
* @Author Becolette
* @Date 2017-4-9 下午07:52:35
* @Modified By Becolette at 2017-4-9 for TODO
*/
public class Test1 {
/**
* @Description TODO
* @Author Becolette
* @Date 2017-4-9 下午07:52:35
* @Modified By Becolette at 2017-4-9 for TODO
*/
public static void main(String[] args) {
Circle circle = new Circle();
DecimalFormat df = new DecimalFormat("#.00");
Scanner input = new Scanner(System.in);
System.out.println("輸入半徑:");
double r = input.nextDouble();
System.out.print("周長=" + df.format(circle.getLength(r)) + " 面積=" + df.format(circle.getArea(r)));
System.out.println("周長=" + df.format(2 * circle.getLength(r)) + " 面積=" + df.format(2 * circle.getArea(r)));
}
}
慕桂英3389331
TA貢獻2036條經驗 獲得超8個贊
public class Circle { private Double radius; public Double getArea() { if (radius == null || radius <= 0) { throw new RuntimeException("radius不合法"); } return Math.PI * radius * radius; } public Double getLength() { if (radius == null || radius <= 0) { throw new RuntimeException("radius不合法"); } return Math.PI * 2 * radius; } public Double getRadius() { return radius; } public void setRadius(Double radius) { this.radius = radius; } } |
import java.util.Scanner; public class App { public static void main(String[] args) { Scanner input = new Scanner(System.in); Circle circle = new Circle(); while (true) { Double radius = input.nextDouble(); circle.setRadius(radius); System.out.println(String.format("%.2f %.2f", circle.getArea(), circle.getLength())); circle.setRadius(radius * 2); System.out.println(String.format("%.2f %.2f", circle.getArea(), circle.getLength())); } }} |
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