What Does the Exclamation Mark Mean in This Line of C18 Code?

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Hi there,
It means 'not equal to'. So the succeeding code (in the while loop) will repeat as long as switch_pin is not equal to 1 (ie while the pin logic value is low).
Hope that helps!
Ant
 
in C/C++/C# there are two negation operators

! negates logic
~ negates on the bit level
 
Depends on what the voice inside of your head tells you! Both answers are right. While not equal to something would be how I do it. While I'm not dry , keep using the towel vs. When I'm dry don't use the towel.

Something to think about!
 
Angry Badger said:
Ok, thanks. So (Switch_Pin == 0); would do it.

Cheers.
Click to expand...

Some coders would write the comparison like this: (0 == Switch_Pin)
So if you accidentally mistype it: (0 = Switch_Pin)
The compiler will detect that and give you an errror, but if you mistype it: (Switch_Pin = 0)
The compiler cannot detect the error you made.

And,
(Switch_Pin == 0)
is not the same as:
(Switch_Pin != 1)

They may produce the same behavior depending how the variable is defined.. and depending on the compiler.
 
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