Prime numbers in Visual Basic 6.0

Prime numbers as other classifications of natural numbers were classified by Pythagoras and his sect, whose members were called Pythagoreans-.

This program will result in the prime numbers from a value to another that we specify.

For the form we'll need 2 textbox (txtFrom and txtTo). Two labels, one listbox (lstResult) and 1 commandbutton (cmdCalculate). As shown in the right image.

In the calculate button insert the following code:

Option Explicit

Dim d, h, v, a, b, c As Integer


Private Sub cmdCalculate_Click()

If Val(txtFrom.Text) < Val(txtTo.Text) Then
lstResult.Clear

d = Val(txtFrom.Text)
h = Val(txtTo.Text)
v = d - 1

Do While v < h
v = v + 1

'Identificar si el numero es primo
a = 0
b = 1


Do While b <= v
c = v Mod b

If c = 0 Then
a = a + 1
b = b + 1

Else
b = b + 1
End If

Loop

If a = 2 Or v = 1 Then

lstResult.AddItem (v)
End If
Loop

Else
MsgBox ("The value of From must be greater tha the value of To")
End If

txtFrom.Text = ""
txtTo.Text = ""
txtFrom.SetFocus

End Sub

Image: Rest up, little Pikachu! by xThunderbolt