How to default-initialize a struct containing an array in Rust?

Question

What is the recommended way to declare a struct that contains an array, and then create a zero-initialized instance?

Here is the struct:

#[derive(De         


        

Answer 1

Rust does not implement Default for all arrays because it does not have non-type polymorphism. As such, Default is only implemented for a handful of sizes.

You can, however, implement a default for your type:

impl Default for Histogram {
    fn default() -> Histogram {
        Histogram {
            sum: 0,
            bins: [0; 256],
        }
    }
}

Note: I would contend that implementing Default for u32 is fishy to start with; why 0 and not 1? or 42? There is no good answer, so no obvious default really.