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Rust 101 - 4: Exercises for module A1
(diode.zone)
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this post was submitted on 14 Feb 2024
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In the last exercise (
05), I ran quickly tried to extend it into creating "unfloored halves" (you'll know what I mean if you look at the exercise) ... and ran into the process of initialising empty arrays.What I hit upon is:
Where the
0.0in[0.0; 5]is necessary it seems?? And you can't simply havelet floating_data = [f32; 5];... ?From what I gathered, the general syntax is
[EXPR; SIZE], whereEXPRis actually evaluated, presumably to define the required memory/type, even though the type of the array (in the code above,f32) also constrains the type of elements of the array.In the code above, as the default float type is
f64, the typing of the array as[f32; 5]actually constrained or affected the way that the expression of0.0in the array literal was used to build the array.So why do I need to provide both so that they interact in this weird and implicit way?? Unless I'm missing something, surely something like
let floating_data = [f32; 5];would be better? Putting that0.0because it just needs to be there is tolerable but a bit off IMO.Shouldn't we be able to do something like
?
I'm on mobile and too lazy to try whipping up a rust playground example to test this out myself.
Thanks!
I recognise I was getting nitpicky there, just figured it might help someone else avoid confusion around it.
And yea, I figured I’d make sure I knew how to set the numeric type of my choice rather than just rely on inference.
Otherwise, I think I hate the postfix typing, I just can’t bring myself to use it lol.
But thanks for the help!!