간단한 재귀하나 해보자

package Class;
import java.sql.Struct;
import java.util.*;

public class FactorialEx{
 public static void main( String[] args ){
  System.out.println( factorial(4) );
 }

 private static int factorial(int i) {
  return ( i == 0)?1:i*factorial(i-1);
 }
}