数组（Arrays）

fn main() {
    let mut a: [i8; 10] = [42; 10];
    a[5] = 0;
    println!("a: {a:?}");
}

A value of the array type [T; N] holds N (a compile-time constant) elements of the same type T. Note that the length of the array is part of its type, which means that [u8; 3] and [u8; 4] are considered two different types. Slices, which have a size determined at runtime, are covered later.
请尝试访问出界数组元素。系统会在运行时检查数组访问。Rust 通常会通过优化消除这些检查，以及使用不安全的 Rust 来避免这些检查。
我们可以使用字面量来为数组赋值。
The println! macro asks for the debug implementation with the ? format parameter: {} gives the default output, {:?} gives the debug output. Types such as integers and strings implement the default output, but arrays only implement the debug output. This means that we must use debug output here.
添加 #，比如 {a:#?}，会输出“美观打印（pretty printing）” 格式，这种格式可能会更加易读。

Comprehensive Rust 🦀