Here a sample program that I wrote in VB.NET to accept a decimal input value and then it will convert it to roman numeral equivalent the code is very simple and easy to understand. I hope you will learn from it. Thank you.
My email address are the following jakerpomperada@gmail.com and jakerpomperada@yahoo.com.
My mobile number here in the Philippines is 09173084360.
Sample Program Output
Program Listing
Public Class Form1
Private Function ConvertToRoman(ByVal input As Integer) As String
Dim numeral As String = String.Empty
If input < 1 OrElse input > 4000 Then
Throw New ArgumentOutOfRangeException("input", input.ToString, "Value must be greater than 0 and less than 4,001.")
Else
Dim numeralDic As Dictionary(Of Integer, String) = New Dictionary(Of Integer, String)
With numeralDic
.Add(1, "I")
.Add(4, "IV")
.Add(5, "V")
.Add(9, "IX")
.Add(10, "X")
.Add(40, "XL")
.Add(50, "L")
.Add(90, "XC")
.Add(100, "C")
.Add(400, "CD")
.Add(500, "D")
.Add(900, "CM")
End With
For x As Integer = 0 To input.ToString.Length - 1
Dim currentValue As Integer = CInt(input.ToString.Substring(x, 1))
If x = input.ToString.Length - 1 Then
If numeralDic.ContainsKey(currentValue) Then
numeral &= numeralDic(currentValue)
ElseIf currentValue < 4 Then
For y As Integer = 1 To currentValue
numeral &= "I"
Next
ElseIf currentValue > 5 Then
numeral &= "V"
For y As Integer = 6 To currentValue
numeral &= "I"
Next
End If
ElseIf x = input.ToString.Length - 2 Then
currentValue = currentValue * 10
If numeralDic.ContainsKey(currentValue) Then
numeral &= numeralDic(currentValue)
ElseIf currentValue < 4 Then
For y As Integer = 1 To currentValue
numeral &= "X"
Next
ElseIf currentValue > 5 Then
numeral &= "L"
For y As Integer = 6 To currentValue
numeral &= "X"
Next
End If
ElseIf x = input.ToString.Length - 3 Then
currentValue = currentValue * 100
If numeralDic.ContainsKey(currentValue) Then
numeral &= numeralDic(currentValue)
ElseIf currentValue < 4 Then
For y As Integer = 1 To currentValue
numeral &= "C"
Next
ElseIf currentValue > 5 Then
numeral &= "D"
For y As Integer = 6 To currentValue
numeral &= "C"
Next
End If
Else
For y As Integer = 1 To currentValue
numeral &= "M"
Next
End If
Next
End If
Return numeral
End Function
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
End Sub
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
End
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Label3.Text = "The Roman Numeral Equivalent of " & Val(TextBox1.Text) & " is " & ConvertToRoman(Val(TextBox1.Text)) & "."
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
TextBox1.Text = ""
Label3.Text = ""
TextBox1.Focus()
End Sub
End Class
