vfp中怎么写分段给成绩等级的程序 用三种循环结构分别

set talk off

use 成绩

for i=1 to recc()

cj=平时成绩*0.2+考试成绩*0.8

do case

case cj>=90

dj="优"

case cj>=75

dj="良"

case cj>=60

dj="及格"

otherwise

dj="不及格"

endcase

repl 等级 with dj

skip

endfor

use

set talk on

input "输入考试成绩" to chj

if chj<60

dj="E"

else

if chj<70

dj="D"

else

if chj<80

dj="C"

else

if chj<90

dj="B"

else

dj="A"

endif

endif

endif

endif

? dj

input SC

do case

case sc<60

?"不及格"

case sc>=60 and sc<90

?"通过"

otherwise

?"优秀"

endcase