I have a problem in Boolean class returning Boolea...

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[Niranjan Kurve]

I have a problem in Boolean class returning Boolean values when compareTo() is overridden and called. As we all know that compareTo() returns Int value whether it is zero, positive or negative. So how can Boolean class implicitly convert it to Boolean form ????????

When I tried to inherit Comparable class on user-defined class it printed same (i.e. Boolean value).



Comparable Class : https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-comparable/#functions
Boolean Class : https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-boolean/compare-to.html

[diesieben07]

> and < use compareTo, but they don't just call compareTo. foo < bar becomes foo.compareTo(bar) < 0

[Niranjan Kurve]

But how they return Boolean instead of Int

[diesieben07]

foo.compareTo(bar) < 0 is a boolean.

[diesieben07]

foo.compareTo(bar) is an int

[Niranjan Kurve]

They return difference between given parameters

[Niranjan Kurve]

So how can it be Boolean s the return type mentioned is Int.

[diesieben07]

Are you even reading what I am saying?

[Niranjan Kurve]

Could you please look at the Program screenshot

[diesieben07]

I did. You are not calling compareTo anywhere.

[Niranjan Kurve]

K

[diesieben07]

You are using < and >. Version(...) > Version(...) becomes Version(...).compareTo(Version(...)) > 0, that is a boolean.

[diesieben07]

If you want the actual result of compareTo you need to use it directly:
Version(...).compareTo(Version(...)), which is an int.

[Niranjan Kurve]

Ok I got it

[Matteo Mirk]

please read about operator overloading to understand how it works

[Niranjan Kurve]

Actually It was returning Int result in println() function so I got bit confused how it can print Boolean value for that.