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#1 2012-03-07 08:28:34
Help ,Help
My project is here :
parachuting跳伞
I 'd like to repeat 10 times
but I don't understand why only run it once
Who can help me ?
Thanks!
Last edited by liupengty (2012-03-07 08:31:18)
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#3 2012-03-07 08:55:03
Re: Help ,Help
when green flag clicked
repeat (10)
set [tiaosanX] to (250)
forever if <(tiaosanX) > [-300]>
change [tiaosanX] by <pick random(-3)to(-1) >
end
end
I 'd like to repeat 10 timesbut I don't understand why only run it once
Last edited by liupengty (2012-03-07 09:21:33)
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#6 2012-03-07 10:05:28
- Hardmath123
- Scratcher
- Registered: 2010-02-19
- Posts: 1000+
Re: Help ,Help
Ok, here's the thing. The forever if block is synonymous to:
forever if <blah> blah endSo as soon as you enter a forever loop, even if it's forever if, you know you will never come out. Like a life sentence. So in your code, the forever block doesn't stop when tiaosanX is less than -300; it keeps waiting for it to get above -300 so it can evaluate again.
Now your solution: it's perfect. "Repeat until" is exactly what you need. Repeat until repeats the given code, until (ha!) the condition given is true. So then tiaosanX is below -300, it stops evaluationg, the program moves on, back to the beginning of the repeat block.
Hope this helped. If not, think of it this way: any block whose bottom if flat (eg forever, forever if, stop all, etc. They're called cap blocks) will never, ever continue evaluation of the script; the evaluation stops at them no matter what. So if you put forever if there, the evaluation of the first repartition will never complete, so you won't see it repeat.
Hardmaths-MacBook-Pro:~ Hardmath$ sudo make $(whoami) a sandwich
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