i$="3*6+4*5^3-48/12"

for i=len(i$) to 1 step -1
  if mid$(i$,i,1)=space$(1) then i$=left$(i$,i-1)+mid$(i$,i+1)
next

su$=""
for k=1 to len(i$)
   k$=mid$(i$,k,1)
   if instr(1,".0123456789", k$)then
      su$=su$+k$
      p=1
   elseif instr(1,"^+-*/\",k$)then
      if p=0 and k$="-" then
         su$=su$+k$
      else
         i=i+1
         f$(i)=k$
         n(i)=val(su$)
         su$=""
      endif
      p=0
   else
      print "算式中有其他非法字符"
   endif
next     
  i=i+1
  f$(i)="end"
  n(i)=val(su$)

if i>m then print "运算的个数超过了";m;"个，请重新修改程序"


do until i=1
   h=h+1
   if h>=i then exit do
   if yun(f$(h+1))<=yun(f$(h)) then
      n(h)=desu(n(h),f$(h),n(h+1))
      i=i-1
      for ii=h to (i-1)
          f$(ii)=f$(ii+1)
          n(ii+1)=n(ii+2)
      next
          f$(ii)=f$(ii+1)
      h=0
   end if
loop
print "运算结果是";n(1)
system

function yun(a$)
yun=(instr(1,"最后 +-   */\  ^    ",a$)+1)\5
'把运算符号分等级，每五个符号为一级吧，当然了，这随你喜欢去更改的
end function

function desu(a,b$,c)
select case b$
case "^"
  desu=a^c
case "*"
  desu=a*c
case "\"
  desu=a\c
case "/"
  desu=a/c
case "+"
  desu=a+c
case "-"
  desu=a-c
case else
''有其他运算规则照样加上去喽
end select
end function