lab_Recursion

package welcome;
import java.io.*;
public class lab_Recursion
{
public static double recursive(double number)
{
if(number==0)
return 0;
else if(number==1)
{
return 1;
}
else return (number*recursive(number-1));
}

public static void main(String[] args) throws IOException
{
double n;
BufferedReader keyboard =new BufferedReader(new InputStreamReader(System.in));
System.out.println("please type positive number");
System.out.println("negative number is end.");
String input = keyboard.readLine();
double temp = Double.parseDouble(input.trim());
n=recursive(temp);
System.out.println(temp+"!="+n);
}
}