#include<stdio.h>#include<stdlib.h>void main(){ int n,i; long sn=0,t=1; system("color 3E"); printf("***输入n***\n"); scanf("%d",&n); for(i=1;i<=n;i++) { t=t*i; sn=sn+t; } printf("1!+2!+3!...+N1=%ld\n",sn);}