Module Module1

    Sub main()
        Do
            Console.WriteLine("輸入兩個數字 進行加減乘除(90字以內)")
            Console.WriteLine("若輸入都是0 則進行讀檔 若都輸入-1 則關閉程式")
            Console.Write("第一數 : ")
            Dim s1, s2 As String
            s1 = Console.ReadLine : Console.Write("第二數 : ") : s2 = Console.ReadLine
            If s1 = "" Then s1 = "0" : If s2 = "" Then s2 = "0"
            If s1 = "0" And s2 = "0" Then
                Dataread() : Exit Sub
            ElseIf s1 = "-1" And s2 = "-1" Then
                Exit Sub
            Else
                edm_cmd(s1, s2)
            End If
        Loop
    End Sub
    Sub Dataread()
        FileOpen(1, "in1.txt", 1)
        FileOpen(2, "in2.txt", 1)
        FileOpen(3, "out.txt", 2)
        For tx = 1 To 2
            Dim a As Integer : Input(tx, a)
            For ty = 1 To a
                Dim s1, s2 As String : s1 = LineInput(tx) : s2 = LineInput(tx)
                If s1 = "" Then s1 = "0" : If s2 = "" Then s2 = "0"
                PrintLine(3, edm_read(s1, s2))
            Next
            PrintLine(3)
        Next
        Console.WriteLine("讀檔輸出完成 程式即將關閉")
    End Sub
    Sub edm_cmd(ByVal a As String, ByVal b As String)
        Dim rua, rub As String : rua = a : rub = b              '將原始兩數儲存
        Dim nega, negb As Boolean : nega = False : negb = False '先判斷是否有負數
        If Mid(a, 1, 1) = "-" Then
            nega = True : a = Mid(a, 2, a.Length) 'a如果是負數 負數提出 nega= true 並將a設為正數
        End If
        If Mid(b, 1, 1) = "-" Then
            negb = True : b = Mid(b, 2, b.Length) 'b如果是負數 負數提出 negb= true 並將b設為正數
        End If
        Dim ap, an, am, aq As String : Dim aout As String = "" : If nega Xor negb Then am = "-" : aq = am '如果ab異號 相乘|相除 會是負數 先將結果添加負數
        ap = qad(a, b, nega, negb, numcheck(a, b)) : Console.WriteLine(rua & " + " & rub & " = " & ap)
        an = qan(a, b, nega, negb, numcheck(a, b)) : Console.WriteLine(rua & " - " & rub & " = " & an)
        am &= qm(a, b) : Console.WriteLine(rua & " * " & rub & " = " & am)
        aq &= qa(a, b, numcheck(a, b)) : Console.WriteLine(rua & " / " & rub & " = " & aq)
    End Sub
    Function edm_read(ByVal a As String, ByVal b As String)
        Dim rua, rub As String : rua = a : rub = b              '將原始兩數儲存
        Dim nega, negb As Boolean : nega = False : negb = False '先判斷是否有負數
        If Mid(a, 1, 1) = "-" Then
            nega = True : a = Mid(a, 2, a.Length) 'a如果是負數 負數提出 nega= true 並將a設為正數
        End If
        If Mid(b, 1, 1) = "-" Then
            negb = True : b = Mid(b, 2, b.Length) 'b如果是負數 負數提出 negb= true 並將b設為正數
        End If
        Dim ap, an, am, aq As String : Dim aout As String = "" : If nega Xor negb Then am = "-" : aq = am '如果ab異號 相乘|相除 會是負數 先將結果添加負數
        ap = qad(a, b, nega, negb, numcheck(a, b)) : ap = rua & " + " & rub & " = " & ap & Chr(13)
        an = qan(a, b, nega, negb, numcheck(a, b)) : an = rua & " - " & rub & " = " & an & Chr(13)
        am &= qm(a, b) : am = rua & " * " & rub & " = " & am & Chr(13)
        aq &= qa(a, b, numcheck(a, b)) : aq = rua & " / " & rub & " = " & aq
        Return aout.ToString
    End Function
    Function numcheck(ByVal a As String, ByVal b As String)           '兩數大小比對
        '設定a,b字串長度 並判斷大小  lx>>2:a大 1:b大 0:都一樣大
        If a = b Then Return 0 : Exit Function '如果a=b 兩數一樣大
        Dim la, lb, lx As Integer : la = a.Length : lb = b.Length     '先設定la,lb 為兩數長度
        If la > lb Then lx = 2 Else If la < lb Then lx = 1 '如果la>lb a大 反之
        If la = lb Then                                               '如果la=lb 進行每個字判斷(由大數->小數)
            For i = 1 To a.Length
                If Val(Mid(a, i, 1)) > Val(Mid(b, i, 1)) Then         '比對相同位數的數字大小
                    lx = 2 : Exit For
                ElseIf Val(Mid(a, i, 1)) < Val(Mid(b, i, 1)) Then
                    lx = 1 : Exit For
                End If
            Next
        End If
        Return lx '完成ab大小判斷
    End Function
    Function qa(ByVal a As String, ByVal b As String, ByVal lx As Integer)    '除法
        If b = "0" Or b = "" Then Return "除數不得為0" : Exit Function
        If a = "0" Or a = "" Then Return "被除數為0 = 0" : Exit Function
        If lx = 1 Then Return "0" : Exit Function
        Dim la, lb As Integer : la = a.Length : lb = b.Length
        Dim tn As String = ""
        For i = lb To la
            Dim stn As String = b
            For j = la - i To 1 Step -1
                stn &= "0"
            Next
            Dim stn2 As String = stn : Dim qot As String = "" : Dim qt As Integer = 0
            Do
                Dim unc As Integer = numcheck(a, stn)
                If unc = 2 Then
                    stn = add(stn, stn2) : qt += 1
                ElseIf unc = 1 Or unc = 0 Then
                    stn = rv(stn, stn2) : Exit Do
                End If
            Loop
            a = rv(a, stn)
            tn &= qt
        Next
        Dim tnl As Integer = 0
        For i = 1 To tn.Length
            If Mid(tn, 1, 1) <> "0" Then Exit For Else tn = Mid(tn, 2, tn.Length)
        Next
        Return tn.ToString
    End Function
    Function qm(ByVal a As String, ByVal b As String)   '乘法
        If a = "0" Or b = "0" Or a = "" Or b = "" Then Return 0 : Exit Function
        Dim lb As Integer = b.Length : Dim lmp(180), lmo As String : lmo = "0"
        For i = 1 To lb
            If lmp(i) = "" Then lmp(i) = "0"
            For j = Val(Mid(b, lb - i + 1, 1)) To 1 Step -1
                lmp(i) = add(lmp(i), a)
            Next
        Next
        For i = 1 To 180
            If lmp(i) = Nothing Then ReDim Preserve lmp(i - 1) : Exit For
        Next
        If lmp.Length > 2 Then
            For i = 2 To lmp.Length - 1
                For j = 2 To i
                    lmp(i) = lmp(i) & "0"
                Next
            Next
        End If
        For i = 1 To lmp.Length - 1
            lmo = add(lmo, lmp(i))
        Next
        Return lmo.ToString
    End Function
    Function qad(ByVal a As String, ByVal b As String, ByVal nega As Boolean, ByVal negb As Boolean, ByVal lx As Integer)  '加法 前置
        If a = "0" Or a = "" Then Return b.ToString : Exit Function
        If b = "0" Or b = "" Then Return a.ToString : Exit Function
        Dim outsp As String = "" : Dim tep As String = ""
        If lx = 0 Then
            If nega Xor negb Then outsp &= 0 Else tep = add(a, a)
            If nega = True And negb = True Then outsp &= "-" & tep
            If nega = False And negb = False Then outsp &= tep
        ElseIf lx = 1 Then
            If nega Xor negb Then tep = rv(b, a) Else tep = add(b, a)
            If negb = True Then outsp &= "-"
            outsp &= tep
        ElseIf lx = 2 Then
            If nega Xor negb Then tep = rv(a, b) Else tep = add(a, b)
            If nega = True Then outsp &= "-"
            outsp &= tep
        End If
        Return outsp.ToString
    End Function
    Function qan(ByVal a As String, ByVal b As String, ByVal nega As Boolean, ByVal negb As Boolean, ByVal lx As Integer)  '減法 前置
        Dim outsp As String = "" : Dim tep As String = ""
        If lx = 0 Then
            If nega = negb Then outsp &= 0 Else tep = add(a, b)
            If nega = True And negb = False Then outsp &= "-" & tep
            If nega = False And negb = True Then outsp &= tep
        ElseIf lx = 1 Then
            If nega Xor negb Then tep = add(b, a) Else tep = rv(b, a)
            If negb = False Then outsp &= "-"
            outsp &= tep
        ElseIf lx = 2 Then
            If nega Xor negb Then tep = add(a, b) Else tep = rv(a, b)
            If nega = True Then outsp &= "-"
            outsp &= tep
        End If
        Return outsp.ToString
    End Function
    Function add(ByVal a As String, ByVal b As String)   '加法(帶進任意兩數相加)
        Dim x(180), y(180) As Integer : ReDim x(180), y(180)
        Dim s_ad As String = ""
        Dim lo, r As Integer : lo = 0 : r = 0
        For i = a.Length To 1 Step -1
            x(a.Length - i) = Val(Mid(a, i, 1))
        Next
        For i = b.Length To 1 Step -1
            y(b.Length - i) = Val(Mid(b, i, 1))
        Next
        If a.Length > b.Length Then lo = a.Length - 1 Else lo = b.Length
        For i = 0 To lo - 1
            x(i) += y(i)
        Next
        Do
            If x(r) >= 10 Then x(r + 1) += 1 : x(r) -= 10 Else r += 1
        Loop Until r = lo
        If x(lo) = 0 Then lo -= 1
        For i = lo To 0 Step -1
            s_ad &= x(i)
        Next
        Return s_ad.ToString
    End Function
    Function rv(ByVal a As String, ByVal b As String)  '減法(帶進任意兩數相減) 前提 a > b
        If a = b Then Return 0 : Exit Function
        If b = "0" Then Return a : Exit Function
        Dim x(180), y(180) As Integer : ReDim x(180), y(180)
        Dim s_ad As String = ""
        Dim lo, r As Integer : lo = 0 : r = 0
        For i = a.Length To 1 Step -1
            x(a.Length - i) = Val(Mid(a, i, 1))
        Next
        For i = b.Length To 1 Step -1
            y(b.Length - i) = Val(Mid(b, i, 1))
        Next
        If a.Length > b.Length Then lo = a.Length - 1 Else lo = b.Length
        For i = 0 To lo - 1
            x(i) -= y(i)
        Next
        Do
            If x(r) < 0 Then x(r + 1) -= 1 : x(r) += 10 Else r += 1
        Loop Until r = lo
        Do
            If x(lo) = 0 Then lo -= 1
        Loop Until x(lo) > 0
        For i = lo To 0 Step -1
            s_ad &= x(i)
        Next
        Return s_ad.ToString
    End Function

End Module