This document provides information on procedures, sub procedures, function procedures, and calling procedures by value and by reference in Visual Basic. It includes examples of defining and calling sub procedures and functions, including passing arguments and returning values. It also covers optional arguments, mathematical functions, string functions, recursion, code modules, and accessing procedures defined in modules from forms.

2. Procedures
Events
Built-invb6
Sub procedures, Function Procedures.
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3. Sub Procedures
:
[Accessing type] sub procedures name ([Parameter
list])
Statements
End sub
:
Procedure name([Parameter List])
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4. Private sub command_click()
Dim x, y, z as integer
X=40
Y=135
Z=90
Max(x,y,z)
End sub
Puplic sub max(a,b,c as integer)
Dim answer as integer
Answer= a
If b >answer then answer=b
If c >answer then answer=c
Print answer
End sub
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5. Sub Functions
SubFunction
Function functionName ([arguments]) as type
Function statements
]Return value[
End function
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6. 'Function Definition
Private Function sum(n1 As Integer, n2 As Integer)
'n1, n2 are parameters
Text1.Text = n1 + n2
End Function
________________________________________
_
Private Sub Form_Load()
Text1.Text = ""
'Function call
Call sum(32, 54) '32 and 54 are arguments
End Sub
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7. 'Function Definition
Private Function sum(n1 As Integer, n2 As Integer) As Integer
'Returns a value
sum = n1 + n2
End Function
_________________________________________
Private Sub Form_Load()
Text1.Text = ""
'Function calling and assigning the returned value
Text1.Text = sum(60, 40)
End Sub
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8. Call By Reference
ByRef
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9. Call By Reference
Private Sub Command1_Click ()
Dim Name As String
Name = “Suha Alaaraj”
Call SetName (Name)
MsgBox Name
End Sub
Private Sub SetName (ByRef n AS String)
MsgBox n
n = “Ali”
End Sub
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10. Call By Value
ByVal
Visual BasicBy References
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11. Call By Value
Private Sub Command1_Click ()
Dim Name As String
Name = “Suha Alaaraj”
Call SetName (Name)
MsgBox Name
End Sub
Private Sub SetName (ByVal n AS String)
MsgBox n
n = “Ali”
End Sub
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12. Optional
Optional
OptionalOptional
Private sub example(x as integer, Optional y as integer)
Call example(12) ‘here x=12 and y=0 by default
Call example(14,35) ‘here x=14 and y=35
Call example(13, ) ‘here x=13 and y=0 by default
5150
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13. Mathematical Functions
Abs(12.3235) ' returns 12.3235
Abs(-10.3) ' returns 10.3
Round(29.03914, 2) ‘you will get 29.04
Sqr(9) ' returns 3
Sgn(-214) ' returns -1
Sgn(313.3) ' returns 1
Exp(1) ' returns e (2.71828182845905)
Exp(2) ' returns e to the power of 2 (7.38905609893065)
Int(5.698) ‘ return 5
Fix(5.698) ‘ return 5
Int(-5.6) ‘return -6
fix(-5.6) ‘return -5
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14. String Functions
Len (VisualBasic) = 11 and Len (welcome to VB
tutorial) = 22
Right(“Visual Basic”, 4) = asic
 Left (“Visual Basic”, 4) = Visu
Trim (“ Visual Basic ”) = Visual basic
Ucase(“Visual Basic”) =VISUAL BASIC
Lcase(“Visual Basic”) =visual basic
Chr(65)=A, Chr(122)=z, Chr(37)=%
 Asc(“B”)=66, Asc(“&”)=38
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15. if for
Private function recfact(n as
integer) as long
If n<=1 then
Recfact=1
Else
Recfact=n * recfact(n-1)
End if
End function
Private function recfact(n
as integer) as long
Dim k as long
K =1
For j=2 to n
K=k*j
Next j
Recfact =k
End function
Recursion
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16. Code Modules




AccessibilityBAS
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17. add - module1
'Inside the BAS Module1
'Scope is Public to make it accessible from anywhere of the
application
Public Sub show()
MsgBox "Welcome to vb6"
Form1.backcolor=vbyellow
Form1.command1.caption=“hellooo suha”
End Sub
____________________________________
Public Function increment(number As Integer) As Integer
increment = number + 1
End Function
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18. Form1
'In form1
Private Sub command1_Click()
Dim num As Integer
num = InputBox("Enter the number", "Input")
MsgBox module1.increment(num)
Module1.show
End Sub
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