CODEWITHSUNDEEP
rust
Maik Klein
Maik Klein

Reputation: 16148

How to call `min` on a generic type that could be either an integer or float?

What do I do when I want to call min on integers and floats? For example consider this:

fn foo<T>(v1: T, v2: T)
    where ???
{
   ....
   let new_min = min(v1, v2);
   ....
}

The problem is that min doesn't work for f32. There is another min for floats.

How would I solve this problem?

Upvotes: 1

Views: 933

Answers (1)

Shepmaster
Shepmaster

Reputation: 430574

Create your own trait that defines the behavior of the various types:

trait Min {
    fn min(self, other: Self) -> Self;
}

impl Min for u8 {
    fn min(self, other: u8) -> u8 { ::std::cmp::min(self, other) }
}

impl Min for f32 {
    fn min(self, other: f32) -> f32 { f32::min(self, other) }
}

fn foo<T>(v1: T, v2: T)
    where T: Min
{
   let new_min = Min::min(v1, v2);
}

As mentioned in other places, floating point comparisons are hard.

There's no one answer to what the result of min(NaN, 0.0) should be, so it's up to you to decide. If you decide that NaN is less than or greater than all other numbers, great! Maybe it's equal to zero! Maybe you should assert that there will never be a NaN...

Upvotes: 5

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