**  主程序
set talk off
clear
use student2
for i=1 to 3 step 1
public a,b,flag
a="******"
b="******"
@ 4,50 say "學(xué)生操作系統(tǒng)"
@ 5,20 say "學(xué)生學(xué)號(hào)" get a
@ 6,20 say "學(xué)生密碼" get b
read
go top
flag=0
do while .not.eof()
if xh=a .and. mm=b
flag=1
endif
skip
enddo
if flag=1
clear
wait "歡迎登陸系統(tǒng)"
do 程序1.prg
**調(diào)用程序1 
do 程序1
clear
else
wait "輸入錯(cuò)誤，請(qǐng)重新輸入"
endif
endfor
wait "3次錯(cuò)誤，自動(dòng)跳出"
return