程序代码：

Clear
Set Escape On
Input To N
m=Replicate("9",N)
a=Right(m,1)
j=1
g=0
For i=Val(a) To 0 Step -1
    IF j=1
      x=Substr(m,1,N-j-1)+Substr(m,N-j,1)+Alltrim(Str(i))
    ELSE
       IF j= n
          x=Substr(m,N-j+1,2)+Alltrim(Str(i))
       else
          x=Substr(m,1,N-j)+Substr(m,N-j+1,1)+Alltrim(Str(i))
       endif
    endif
    If Alltrim(Str(i))='0'
        ?Transform(x)
    Endif
    If i=0
        If Val(Substr(x,N-j+1,1))-1=-1    &&判断将要减1的位数是否为0
            For u=j+1 To N Step +1
                If Val(Substr(x,N-u+1,1))-1<>-1  &&判断将要减1的位数是否为0
                    g=u
                    z=Replicate("9",u-1)
                    x=Alltrim(Substr(x,1,N-u))+Alltrim(Str(Val(Substr(x,N-u+1,1))-1))+z
                    m=x
                    u=N+1
                    j=j+1
                    i=9
                Endif
            Endfor
*!*             ELSE
*!*                if  Val(Substr(x,N-g+2,1))-1<>-1
*!*                   z=Replicate("9",g-2)
*!*                   x=Alltrim(Substr(x,1,N-g+1))+Alltrim(Str(Val(Substr(x,N-g+2,1))-1))+z
*!*                   i=9
*!*                   m=x
*!*                else
*!*                   z=Replicate("9",g-1)
*!*                   x=Alltrim(Substr(x,1,N-g))+Alltrim(Str(Val(Substr(x,N-g+1,1))-1))+z
*!*                   i=9
*!*                   m=x
*!*                endif
        ENDIF
    endif
        ?Transform(x)
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