数组（Arrays）

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

This slide should take about 5 minutes.

  • 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。