在本教程中,我们将看到如何在 Java 中计算圆的面积和周长。有两种方法可以做到这一点:
1)用户交互:程序将提示用户输入圆的半径
2)没有用户交互:半径值将在程序本身中指定。
计划 1:
/**
* @author: BeginnersBook.com
* @description: Program to calculate area and circumference of circle
* with user interaction. User will be prompt to enter the radius and
* the result will be calculated based on the provided radius value.
*/
import java.util.Scanner;
class CircleDemo
{
static Scanner sc = new Scanner(System.in);
public static void main(String args[])
{
System.out.print("Enter the radius: ");
/*We are storing the entered radius in double
* because a user can enter radius in decimals
*/
double radius = sc.nextDouble();
//Area = PI*radius*radius
double area = Math.PI * (radius * radius);
System.out.println("The area of circle is: " + area);
//Circumference = 2*PI*radius
double circumference= Math.PI * 2*radius;
System.out.println( "The circumference of the circle is:"+circumference) ;
}
}
输出:
Enter the radius: 1
The area of circle is: 3.141592653589793
The circumference of the circle is:6.283185307179586
程序 2:
/**
* @author: BeginnersBook.com
* @description: Program to calculate area and circumference of circle
* without user interaction. You need to specify the radius value in
* program itself.
*/
class CircleDemo2
{
public static void main(String args[])
{
int radius = 3;
double area = Math.PI * (radius * radius);
System.out.println("The area of circle is: " + area);
double circumference= Math.PI * 2*radius;
System.out.println( "The circumference of the circle is:"+circumference) ;
}
}
输出:
The area of circle is: 28.274333882308138
The circumference of the circle is:18.84955592153876