import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); int n = sc.nextInt(); int sum = 0; int times =1; for(int i = 1; i <= n; i++){ times = times * i; sum += times; } System.out.println(sum); } }定义一个算阶乘,一个计算和的变量,在输出计算和的变量就行。