BlitzCoder Code Database

BlitzCoder Essentials

•Home Page
•About BlitzCoder
•Contributors
•Terms of Use
•Email Us

Main Areas

•BlitzCoder Chat
•Discussions
•Articles/Tutorials
•Code Database
•Link Database
•Showcase Area
•Worklogs
•Competitions

Special Areas

•Undocumented

Other Blitz Sites

•Blitz Basic Home
•Blitz Showcase
•BlitzPlay Library

BlitzCoder Code Archives Page

Main Codes Page

"Optional Parameters in Functions", by ghost dancer

Not sure if this is undocumented, but it is certainly difficult to find! Anyway, it shows you how to use optional parameters in your functions!

Code

;Simple demo of using optional parameters in functions.
;By Ghost Dancer

;Although I'm sure this is documented somewhere, it is difficult to find!

;This gives you great flexibility in your coding - I have my own library of generic functions which is used by
;most of my programs. This is great if find when I need to add a param to the function without affecting existing
;code that uses it - I just make the new param an optional one  :-)

AppTitle "Optional Function Parameters"
Graphics 800, 600

textBox("Test 1 - specifying border gap of 10 pixels", 50, 100, 10)
textBox("Test 2 - using default value", 50, 200)

WaitKey
End

Function textBox(textString$, x, y, borderGap = 2)
     ;Note that it is not really optional, we are just supplying a default value
     ;which gets used if none is specified!
     ;All params you pass to the function after the optional one(s) must also be optional

xPos = x - borderGap - 1                                             ;specified x position, minus gap, minus actual border
     yPos = y - borderGap - 1                                             ;specified y position, minus gap, minus actual border
     width = StringWidth(textString) + (borderGap * 2) + 2          ;string width, + gap each side, + border each side
     height = StringHeight(textString) + (borderGap * 2) + 2          ;string width, + gap each side, + border each side
     
     Rect xPos, yPos, width, height, False
     Text x, y, textString

End Function

Code software created by Krylar's Kreations