#include "
stdio.h"
#include "
stdlib.h"
int main(void){
int n,i,sum,t;
printf("Input n(int 0<n<13)...\nn=");
if(scanf("%d",&n),n<0 || n>12){
printf("Input error, the program exits...\n");
exit(0);
}
for(sum=0,t=i=1;i<=n;sum+=t*=i++);
printf("The result is %d\n",sum);
return 0;
}本回答被提问者采纳