A working Cone
is below.
Copy it to a file and run it with ConeTester
.
More methods need to be added to Cone
,
but it is good to compile and run programs as soon as possible
to find bugs and design errors.
// file: Cone.java // public class Cone { private double radius; // radius of the base private double height; // height of the cone public Cone( double radius, double height ) { this.radius = radius; this.height = height; } public double area() { return Math.PI*radius*(radius + Math.sqrt(height*height + radius*radius) ); } public double volume() { return Math.PI*radius*radius*height/3.0; } }
// file: TestCone.java // import java.util.Scanner ; public class TestCone { public static void main( String[] args ) { Scanner scan = new Scanner(System.in); double radius, height; System.out.print("Enter radius: " ); radius = scan.nextDouble(); System.out.print("Enter height: " ); height = scan.nextDouble(); Cone cone = new Cone( radius, height ); System.out.println( "Area " + cone.area() + " Volume: " + cone.volume() ); } }
Each class is contained in a separate file.
The volume()
method returns a
double
value to the caller.
Since it returns a value,
there must be a return
statement
within its body that returns a value of the
correct type.
When you compile this program how many class files will there be?