Computer Science Canada

Kind of Stupid Question (+=,-=)
Author:  Mr.Programmer [ Wed Feb 27, 2008 7:15 pm ]
Post subject:  Kind of Stupid Question (+=,-=)
My question is, what do these two things mean: ' += ' and ' -="?

I know that := means 'becomes', but these two i cant figure out. Here's an example:

vely -= GRAVITY
posx += round (velx)
posy += round (vely)

Thanks!
Author:  Tony [ Wed Feb 27, 2008 7:24 pm ]
Post subject:  RE:Kind of Stupid Question (+=,-=)
var += 42
is the short way of saying
var := var + 42
Author:  Mr.Programmer [ Wed Feb 27, 2008 7:26 pm ]
Post subject:  Re: Kind of Stupid Question (+=,-=)
Ohhh. Then i guess var -= 22 is like saying ' var :+ var - 22 '?

If so then it makes sense.

And thank you very much.
Author:  Bored [ Thu Feb 28, 2008 7:26 pm ]
Post subject:  Re: Kind of Stupid Question (+=,-=)
There's also other including *=, /=, div=, and I beleive there might be more that I'm missing.
Author:  BigBear [ Thu Feb 28, 2008 7:34 pm ]
Post subject:  Re: Kind of Stupid Question (+=,-=)
when you use := it means becomes or is therefore equal to and when you use += it means becomes itself plus whatever is next
code:
So
var word : string := "" %declares it as nothing
word := word +"hello" %is the same as
word+=word

-= means becomes itself - something
code:

var num : int
put "Enter a number: "..
get num
num -= 2
put "Your number minus 2 is equal to ", num %even though you got num you change it to num := num - 2

You were a little confused when you said
Mr.Programmer wrote:

Ohhh. Then i guess var -= 22 is like saying ' var + var - 22 '?

If so then it makes sense.

And thank you very much.
Author:  Clayton [ Thu Feb 28, 2008 9:33 pm ]
Post subject:  RE:Kind of Stupid Question (+=,-=)
I very much believe the :+ was a typo.

:


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