Calculate area and circumference of circle
how to calculate area and circumference of circle in Java. There are two ways to do this:
1) With user interaction: Program will prompt user to enter the radius of the circle
2) Without user interaction: The radius value would be specified in the program itself.
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) ;
}
}
Output
Enter the radius: 1
The area of circle is: 3.141592653589793
The circumference of the circle is:6.283185307179586
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) ;
}
}
The area of circle is: 28.274333882308138
The circumference of the circle is:18.84955592153876