// app6_12, 簡單的遞歸method
public class app6_12
{
   public static void main(String args[])  
   {
      System.out.println("1*2*..*4 = "+fac(4)); 
   }  
  
 
   public static int fac(int n)  // fac() method
   {
      if(n==1)        // 設置終止條件
         return 1;
      else 
         return n*fac(n-1);   // 遞歸計算
   }
}