by Thomas D. Tomlins (2 Submissions)
Category: Math/Dates
Compatability: Visual Basic 3.0
Difficulty: Advanced
Date Added: Wed 3rd February 2021
Rating: 
(2 Votes)
Determine if a number is Prime if it is not prime return Factors of the number
Inputs
Long number
Code Returns
If not prime returns factors otherwise returns that the number is Prime
Side Effects
None Known
VBcodersOption Explicit
'Add two textboxes 1- txtFactors(Returns Factors) and 1- Text1(Input number
'Two commandbuttons 1-cmdPrimeand 1-cmdPrime2
'One Label 1-Label2
Private Sub cmdPrime_Click()
Dim I As Long, J As Long, Num As Long
Num = Val(Text1.Text)
If Num <= 3 Then
Label2.Caption = "Entry is Prime"
Exit Sub
End If
If Num Mod 2 = 0 Then
Label2.Caption = "Entry is Not Prime"
Exit Sub
End If
I = Int(Sqr(Num)) ' Should be Sqrt(Num)
For J = 3 To I Step 2
If Num Mod J = 0 Then
Label2.Caption = "Entry is Not Prime"
Exit Sub
End If
Next J
Label2.Caption = "Entry is Prime"
End Sub
Private Sub cmdPrime2_Click()
Dim Factors As New Collection
Dim I As Long, J As Long, K As Long, L As Long, Num As Long
Num = Val(Text1.Text)
I = Int(Sqr(Num)) ' Should be Sqrt(Num)
For J = 2 To I
If Num Mod J = 0 Then
L = Factors.Count \ 2
K = Num \ J
If Factors.Count > 0 Then
Factors.Add J, , , L
If (K <> J) Then Factors.Add K, , , L + 1
Else
Factors.Add J
If (K <> J) Then Factors.Add K
End If
End If
Next J
If Factors.Count = 0 Then
txtFactors.Text = Text1.Text & " is prime."
Else
txtFactors.Text = Text1.Text & " is not prime." & vbCrLf
txtFactors.Text = txtFactors.Text & "It is divisible by "
For I = 1 To Factors.Count
txtFactors.Text = txtFactors.Text & Factors.Item(I) & " ,"
Next I
End If
End Sub
