int with leading zero, why breaks after 07?

Programming Questions

v.k.

int with leading zero, why breaks after 07?

in Programming Questions • 10 months ago

Why this does not work?

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void setup(){
int s = 08;
}

but this does...

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void setup(){
int s = 07;
}

Replies(7)

GoToLoop

Re: int with leading zero, why breaks after 07?

10 months ago

Octal numbers don't have digits 8 & 9. Their range is from 0 until 7!
Any number prefixed w/ leading 0(s) is interpreted as an octal literal!

A quick example...
Octal literal 0400 = decimal literal 256:

int s = 000400;
println(s);
exit();

v.k.

Re: int with leading zero, why breaks after 07?

10 months ago

Hummm octal wtf!! I want decimal ints. Thanks for explaining. I was getting a video time code string like "12:43:34:20", spliting and converting to ints to do some math... When I had, for instance, "00:10:10:09" i felt in this octal world with "unexpected token 9" error, i guess i need to check for a leading zero... can it be, kind of, casted? Thanks.

GoToLoop

Re: Re: int with leading zero, why breaks after 07?

10 months ago

I believe function int() can act as a trustful converter, bypassing the dangerous initial leading zeros.
Dunno why your conversion coulda fallen into an octal trap though!

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int octal = 000400;
println(octal);

String s = "000400";
println(s);

int decimal = int(s);
println(decimal);

exit();

v.k.

Re: int with leading zero, why breaks after 07?

10 months ago

Thanks, i have tried this, but unsuccessfully, now, after your example I found my mistake somewhere else.

Happens that i made a TimeCode class, with two constructors, one takes a string, other takes a int to initialize the time code to that time. Either a string "00123019" or an int 00123019, were position would indicates if means hours, minutes, seconds or frames, like color in Processing "HHMMSSFF", but bumped on this... I'll see... Thanks again.

PhiLho

Re: int with leading zero, why breaks after 07?

10 months ago

See also https://forum.processing.org/topic/issue-with-integer-division-of-zero-padded-integers
Funny how some topics come close in time, even if from unrelated paths.

GoToLoop

Re: Re: int with leading zero, why breaks after 07?

10 months ago

Very true, PhiLho! In this month only, there were 2 other posts mentioning octals; even though it was myself who introduced this curious subject! (^_^):

need-help-with-color-program

processing-2-0-changed-how-pixels-works

v.k.

Re: int with leading zero, why breaks after 07?

10 months ago

What do I need octal for...

Thanks guys. I sticked to strings to pass time code values.

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