动手动脑

import java.math.BigInteger;
import java.util.Scanner;


public class CalculateN {

    /**
     * @param args
     */
    public static void main(String[] args) {
        System.out.print("������N��");
        Scanner scanner=new Scanner(System.in);
        int number=scanner.nextInt();
        System.out.println(number+"!="+calculateN2(number));
        
    }
    
    public static long calculateN(int n) {
        if(n==1 || n==0){
            return 1;
        }
        
        return n*calculateN(n-1);
    }

    public static BigInteger calculateN2(int n) {
        if(n==1 || n==0){
            return BigInteger.valueOf(1);
        }
        return BigInteger.valueOf(n).multiply(calculateN2((n-1)));
    }
}

public class CompareFloatNumber {

    /**
     * @param args
     */
    public static void main(String[] args) {
        //compare();
        compare2();

    }

    private static void compare() {
        double i = 0.0001;
        double j = 0.00010000000000000001;
        System.out.println(i==j);  //�����true
    }
    private static void compare2() {
        double i = 0.0001;
        double j = 0.00010000000000000001;
        if(Math.abs(i-j)<1e-10){
            System.out.println("true");  
        }
        else
        {
            System.out.println("false");
        }
        
    }

}