第八周求值

<img src="http://img.blog.csdn.net/20161023155325405?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center" alt="" />#include <stdio.h>#include <math.h>int main ( ){  long int  n,j,c,sn=1,cn=0;  scanf("%ld",&n);  for(j=1;j<=n;j++)  {    sn=sn*j;    cn=cn+sn;  }  printf("%ld",cn);    return 0;}