Example we want to find factorial of 4. Then we multiply 1*2*3*4 = 12. So we can do this with VB6 code. First we set an initial value to start from. Then we run a loop for the nth term (of which we have to find the factorial.) we multiply the i of the loop with the previous result. That is stored in a separate variable. That value is updated in each step of the loop. At last when all the terms have been multiplied to it, it returns us the factorial value. See the code below.

Dim nVal As Long

Dim gVal As Long

Dim i As Integer

txtNo = Trim$(txtNo)

If Len(txtNo) = 0 Then

MsgBox "Enter number", vbCritical, "Input error"

txtNo.SetFocus

Exit Sub

Else

If Not IsNumeric(txtNo) Then

MsgBox "Only numeric input allowed", vbCritical, "Input error"

txtNo.SetFocus

Exit Sub

End If

End If

nVal = 1

gVal = CLng(txtNo.Text)

For i = 2 To gVal

nVal = nVal * i

Next i

MsgBox "The Factorial for " & CStr(gVal) & " is " & CStr(nVal)

End Sub