//計算n!
public class Exception7
{
	public static double multi(int n)
	{
		if (n < 0)
			throw new IllegalArgumentException("輸入了負數異常");
		double s = 1;
		for (int i=1; i<=n; i++) 
			s = s *i;
		return s;
	}
	public static void main(String args[])
	{
		try
		{
			int n = Integer.parseInt(args[0]);
			System.out.println( n + "!=" + multi(n));
		}
		catch (ArrayIndexOutOfBoundsException e)
		{	System.out.println("應該輸入一個整數");	}
		catch (NumberFormatException e2)
		{	System.out.println("應該輸入一個數");	}
		catch (IllegalArgumentException e3)
		{	System.out.println("出現的異常為: "+e3.toString());	} 
		finally
		{	System.out.println("計算階乘結束");}
	}
}