public class TestDemo{
public static int fac(int n){
if(n == 1){ //1!=1
return 1;
}
int tmp = n * fac(n-1); //5!=5*4! //4!=4*3! //所以得出n!=n*(n-1)!
return tmp ;
}
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("请输入数字:");
int n = scanner.nextInt();
System.out.println(fac(n));
}
}