输入一个正整数n 计算并输出n的阶乘

//fliename:Meiri.javaimport java.util.Scanner;public class Meiri{public static void main(String[]args){Scanner reader=new Scanner(System.in);int i,s=1,n=1,m=0;do{System.out.print("输入正整数");i=reader.nextInt();}while(i<=0);for(n=1;n<=i;n++){s=s*n;m+=s;}System.out.println("Sum"+"="+m);}}