rustlings中文指南Appearance
变量1：exercises/variables/variables1.rs
题目
rust
// variables1.rs
//
// Make me compile!
//
// Execute `rustlings hint variables1` or use the `hint` watch subcommand for a
// hint.
// I AM NOT DONE
fn main() {
x = 5;
println!("x has the value {}", x);
}题目解析
错误提示信息如下：
txt
⚠️ Compiling of exercises/variables/variables1.rs failed! Please try again. Here's the output:
error[E0425]: cannot find value `x` in this scope
--> exercises/variables/variables1.rs:11:5
|
11 | x = 5;
| ^
|
help: you might have meant to introduce a new binding
|
11 | let x = 5;
| +++
error[E0425]: cannot find value `x` in this scope
--> exercises/variables/variables1.rs:12:36
|
12 | println!("x has the value {}", x);
| ^ not found in this scope
error: aborting due to 2 previous errors首先提示我们可能时要引入一个新的绑定，建议我们添加let关键字，并提示x在当前作用域下未找到。
正是如此，如果我们要创建一个变量，必须使用let语句。
所以修改后如下：
rust
fn main() {
x = 5;
let x = 5;
println!("x has the value {}", x);
}笔记
所有的变量创建，都需要使用let进行绑定。