Functions
There are many (and i really mean many) built-in functions in VB that are time savers. From functions that show you the date and time to currency. Anyway, lets get reeaadddyyy tooooo reeaaaddddd -I mean rumble!
Tip: Functions are statements that return values, for example Tan(x) returns the tangent of angle x. Tangent is a mathematical function.
These are Numerical & String functions
| Abs() | Returns the absolute number |
| Atn() | Returns the arc tangent |
| Cos() | Returns the cosine value |
| Exp() | Returns the constant raised to the power |
| Rnd() | Returns a random number |
| Sqr() | Returns the square root |
| Str() | Converts a number to a numeric string value |
| Tan() | Returns the tangent of the angle |
| Val() | Converts a numeric string value to a number |
| LCase(Str) | Returns that string in all lower case letters |
| Len(Str) | Returns the number of characters in that string |
| LTrim(Str) | Returns the string w/ any leading spaces cut off |
| RTrim(Str) | Returns the string w/ any ending spaces cut off |
| Str() | Converts the numeric argument to a string w/ numeric digits in the string |
| UCase(Str) | Returns string in all uppercase letters |
OK, so your thinking your never going to need to know all of these, trust me, there might be a few you won't ever use in your life, but your going to end up using some of these if your really serious about programming.
Here are some examples of how to use these functions:
Private Sub Command1_Click()
Dim Text As String
Text = Text1.Text
Label1.Caption = LTrim(Text)
Returned the string with all leading spaces trimmed off
End Sub
Private Sub Command1_Click()
Dim Value
Value = Text1.Text
If (Len(Value) <= 5) Then
5 letters or less
MsgBox "It's small enough!"
Else
6 letters or more
MsgBox "It's too big!"
End If
End Sub
More functions below on Date & Time
| Date | Returns the date |
| Now | Returns the current date & time |
| Time | Returns the current time |
| Timer | Returns the number of seconds its been after midnight |
If you were using a function from above your code could look something like this:
Private Sub Command1_Click()
Label1.Caption = Now labels caption shows what time it is now
End Sub
Tip: This section doesn't cover all the time saving functions in VB but mostly the majority, the truth is there's just too many
More time saving functions...
| IsNull() | It's true if it's null (meaning blank) |
| IsNumeric() | It's true if it can be converted to a Numeric data |
Heres an example of how you would use them;
If IsNumeric(txtCost.Text) = True Then 'Checking to see if its a # (This would be good for use w/ a calculator application b/c you would get an error if the user has entered a string so therefore it should only except integers)
Yet again More functions
| CCur() | Converts whatever's in the () to the equivalent amount of currency |
| Int() | Rounds the number to less then or equal to the () |
And that's that... Next, Modular Programming.
