Pad

Syntax:

    out_string = Pad( string_variable, byte_value_of_the_new_length, pad_character)

Command Availability:

Available on all microcontrollers.

Explanation:

The Pad function creates a string of a specific length, extended with a specific character.

The length of the string is specified by the second parameter. The character used to pad the string is specified by the third parameter.

A typical use is to pad a string to a fixed width before displaying it on an LCD, so that shorter strings do not leave stale characters from a previous, longer string on screen.

Example:

 'Set chip model
    #chip 16f877a


    DIR PORTA 0x03


    ' make port C as output
    Dir PortC 0x0


    'Defines (Constants)
    #define LCD_SPEED slow
    #define LCD_IO 4
    #define LCD_WIDTH 20                ;specified lcd width for clarity only.  20 is the default width
    #define LCD_NO_RW
    #define LCD_Enable PORTc.0
    #define LCD_RS PORTc.1
    #define LCD_DB4 PORTa.5
    #define LCD_DB5 PORTa.4
    #define LCD_DB6 PORTa.3
    #define LCD_DB7 PORTa.2
    '''--------------------------------------------
    '''-------End of board-specific settings-------
    '''--------------------------------------------


    '''DEMO for pad strings to a length
    '''1st character of a given string.
    '''if no string is given, blanks are used


    ; ---- variables
    'Define the string
    Dim TestData As String * 16
    TestData = "Location"

    'show results on LCD-Display
    cls
    Print Pad ( TestData, 16, "*" )          ' <<< the Pad instruction, padded with a visible character
    Locate 1,0
    Print Pad ( TestData, 16, )


    end

Key line: Pad ( TestData, 16, "*" ) — extends "Location" out to 16 characters with trailing asterisks, so the padded text always occupies the same width on the LCD regardless of the source string’s length.

See Also:

  • Left — extracting a fixed-width prefix instead of padding out to one
  • Asc — related command in the same category
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