编写一个VFP程序 求1!+2!+3!+...+n!的值

set talk off
clear
input "输入N值：" to n
s=0
FOR i=1 TO n
a=1
FOR j=1 TO i
a=a*j
ENDFOR
s=s+a
ENDFOR
"1!+2!+3!+...+n!=",s
set talk on
return