3.guessing_game 猜数游戏

3.guessing_game/Cargo.toml

@@ -6,3 +6,4 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+rand = "0.8.4"

3.guessing_game/src/main.rs

@@ -1,11 +1,18 @@
 // 默认 导入 prelude
 
+use std::cmp::Ordering;
 // 使用 库
 use std::io;
+use rand::Rng; // trait
 
 fn main() {
     println!("猜数游戏");
 
+    let secret_number = rand::thread_rng() // 随机数生成器
+        .gen_range(1..100); // 生成随机数
+
+    println!("随机数为: {}", secret_number);
+
     // 声明变量
     // let foo = 1;
     // let bar = foo; // immutable
@@ -13,6 +20,8 @@ fn main() {
     // rust 中 所有变量默认为不可变
     // foo = 2; // 抛错
 
+    loop {
+        println!("请猜一个数");
         // 声明变量时 添加 mut 关键字 为可变变量
         let mut guess = String::new(); // 创建空字符串 实例
 
@@ -22,5 +31,24 @@ fn main() {
             // 捕获异常
             .expect("读取失败");
 
-    println!("猜测的值为 {}",guess)
+        println!("猜测的值为 {}", guess.trim());
+
+        // shadow 隐藏
+        let guess: u32 = match guess.trim().parse() { // 处理错误
+            Ok(num) => num,
+            Err(_) => {
+                println!("请输入数字");
+                continue
+            },
+        };
+
+        match guess.cmp(&secret_number) {
+            Ordering::Less => println!("太小了"),
+            Ordering::Greater => println!("太大了"),
+            Ordering::Equal => {
+                println!("猜对了");
+                break;
+            },
+        }
+    }
 }