Balanced ternary: Difference between revisions
→{{header|Tcl}}
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a*(b-c) = ----0+--0++0 (== -262023)
</pre>
=={{header|Visual Basic .NET}}==
{{trans|C#}}
<lang vbnet>Imports System.Text
Module Module1
Sub Main()
Dim a As New BalancedTernary("+-0++0+")
Console.WriteLine("a: {0} = {1}", a, a.ToLong)
Dim b As New BalancedTernary(-436)
Console.WriteLine("b: {0} = {1}", b, b.ToLong)
Dim c As New BalancedTernary("+-++-")
Console.WriteLine("c: {0} = {1}", c, c.ToLong)
Dim d = a * (b - c)
Console.WriteLine("a * (b - c): {0} = {1}", d, d.ToLong)
End Sub
Class BalancedTernary
Private Enum BalancedTernaryDigit
MINUS = -1
ZERO = 0
PLUS = 1
End Enum
Private ReadOnly value() As BalancedTernaryDigit
' empty = 0
Public Sub New()
ReDim value(-1)
End Sub
' create from string
Public Sub New(str As String)
ReDim value(str.Length - 1)
For i = 1 To str.Length
If str(i - 1) = "-" Then
value(i - 1) = BalancedTernaryDigit.MINUS
ElseIf str(i - 1) = "0" Then
value(i - 1) = BalancedTernaryDigit.ZERO
ElseIf str(i - 1) = "+" Then
value(i - 1) = BalancedTernaryDigit.PLUS
Else
Throw New ArgumentException("Unknown Digit: " + str(i - 1))
End If
Next
Array.Reverse(value)
End Sub
' convert integer
Public Sub New(l As Long)
Dim value As New List(Of BalancedTernaryDigit)
Dim sign = Math.Sign(l)
l = Math.Abs(l)
While l <> 0
Dim remainder = CType(l Mod 3, Byte)
If remainder = 0 OrElse remainder = 1 Then
value.Add(remainder)
l /= 3
ElseIf remainder = 2 Then
value.Add(BalancedTernaryDigit.MINUS)
l = (l + 1) / 3
End If
End While
Me.value = value.ToArray
If sign < 0 Then
Invert()
End If
End Sub
' copy constructor
Public Sub New(origin As BalancedTernary)
ReDim value(origin.value.Length - 1)
Array.Copy(origin.value, value, origin.value.Length)
End Sub
' only for internal use
Private Sub New(value() As BalancedTernaryDigit)
Dim endi = value.Length - 1
While endi > 0 AndAlso value(endi) = BalancedTernaryDigit.ZERO
endi -= 1
End While
ReDim Me.value(endi)
Array.Copy(value, Me.value, endi + 1)
End Sub
' invert the values
Private Sub Invert()
For i = 1 To value.Length
value(i - 1) = CType(-CType(value(i - 1), Integer), BalancedTernaryDigit)
Next
End Sub
' convert to string
Public Overrides Function ToString() As String
Dim result As New StringBuilder
Dim i = value.Length - 1
While i >= 0
If value(i) = BalancedTernaryDigit.MINUS Then
result.Append("-")
ElseIf value(i) = BalancedTernaryDigit.ZERO Then
result.Append("0")
ElseIf value(i) = BalancedTernaryDigit.PLUS Then
result.Append("+")
End If
i -= 1
End While
Return result.ToString
End Function
' convert to long
Public Function ToLong() As Long
Dim result = 0L
For i = 1 To value.Length
result += value(i - 1) * Math.Pow(3.0, i - 1)
Next
Return result
End Function
' unary minus
Public Shared Operator -(origin As BalancedTernary) As BalancedTernary
Dim result As New BalancedTernary(origin)
result.Invert()
Return result
End Operator
' addition of digits
Private Shared carry = BalancedTernaryDigit.ZERO
Private Shared Function Add(a As BalancedTernaryDigit, b As BalancedTernaryDigit) As BalancedTernaryDigit
If a <> b Then
carry = BalancedTernaryDigit.ZERO
Return a + b
Else
carry = a
Return -CType(b, Integer)
End If
End Function
' addition of balanced ternary numbers
Public Shared Operator +(a As BalancedTernary, b As BalancedTernary) As BalancedTernary
Dim maxLength = Math.Max(a.value.Length, b.value.Length)
Dim resultValue(maxLength) As BalancedTernaryDigit
For i = 1 To maxLength
If i - 1 < a.value.Length Then
resultValue(i - 1) = Add(resultValue(i - 1), a.value(i - 1))
resultValue(i) = carry
Else
carry = BalancedTernaryDigit.ZERO
End If
If i - 1 < b.value.Length Then
resultValue(i - 1) = Add(resultValue(i - 1), b.value(i - 1))
resultValue(i) = Add(resultValue(i), carry)
End If
Next
Return New BalancedTernary(resultValue)
End Operator
' subtraction of balanced ternary numbers
Public Shared Operator -(a As BalancedTernary, b As BalancedTernary) As BalancedTernary
Return a + (-b)
End Operator
' multiplication of balanced ternary numbers
Public Shared Operator *(a As BalancedTernary, b As BalancedTernary) As BalancedTernary
Dim longValue = a.value
Dim shortValue = b.value
Dim result As New BalancedTernary
If a.value.Length < b.value.Length Then
longValue = b.value
shortValue = a.value
End If
For i = 1 To shortValue.Length
If shortValue(i - 1) <> BalancedTernaryDigit.ZERO Then
Dim temp(i + longValue.Length - 2) As BalancedTernaryDigit
For j = 1 To longValue.Length
temp(i + j - 2) = CType(shortValue(i - 1) * longValue(j - 1), BalancedTernaryDigit)
Next
result += New BalancedTernary(temp)
End If
Next
Return result
End Operator
End Class
End Module</lang>
{{out}}
<pre>a: +-0++0+ = 523
b: -++-0-- = -436
c: +-++- = 65
a * (b - c): ----0+--0++0 = -262023</pre>
{{omit from|Brlcad}}
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