Imports System
Module Program
' function to compute whether a binary number is divisible by 5
' it processes the bits left to right and keeps track of the remainder modulo 5
' for each bit b:
' remainder = (remainder * 2 + b) Mod 5
Function IsDivisibleByFive(bin As String) As Boolean
' remainder modulo 5 while scanning bits
Dim remainder As Integer = 0
' scan each bit of the binary number
For Each bit As Char In bin
' convert "0" or "1" to integer 0 or 1
Dim b As Integer = Convert.ToInt32(bit) - Convert.ToInt32("0"c)
' update remainder using modulo arithmetic
remainder = (remainder * 2 + b) Mod 5
Next
' divisible if final remainder is zero
Return remainder = 0
End Function
Sub Main()
' read an n-bit binary number as a string
Dim bin As String = "01000110" ' 70
Dim divisible As Boolean = IsDivisibleByFive(bin)
Console.WriteLine("Binary number: " & bin)
Console.WriteLine("Divisible by 5: " & If(divisible, "yes", "no"))
'
' Example walk-through for bin = 01000110:
'
' Start: remainder = 0
'
' bit = 0 → remainder = (0*2 + 0) Mod 5 = 0
' bit = 1 → remainder = (0*2 + 1) Mod 5 = 1
' bit = 0 → remainder = (1*2 + 0) Mod 5 = 2
' bit = 0 → remainder = (2*2 + 0) Mod 5 = 4
' bit = 0 → remainder = (4*2 + 0) Mod 5 = 3
' bit = 1 → remainder = (3*2 + 1) Mod 5 = 2
' bit = 1 → remainder = (2*2 + 1) Mod 5 = 0
' bit = 0 → remainder = (0*2 + 0) Mod 5 = 0
'
' Final remainder = 0 → divisible by 5
'
End Sub
End Module
'
' run:
'
' Binary number: 01000110
' Divisible by 5: yes
'
