fix a little problem

This commit is contained in:
Lam 2018-12-06 15:41:44 +08:00
parent 12d24ab7f0
commit 737d742c15

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@ -349,6 +349,8 @@ rand = "0.4.0"
<span class="filename">文件名: src/main.rs</span>
```rust,ignore
extern crate rand;
use std::io;
use rand::Rng;