pb制作计算器

等号"="代码
double buf
buf=double(buffer)
CHOOSE CASE judge
CASE 1
result=result*buf
CASE 2
result=result/buf
CASE 3
result=result+buf
CASE 4
result=result - buf
END CHOOSE
if result<1000000000 then
sle_1.text=string(result)
else
sle_1.text="error"
end if
buffer=""
judge=0