87 lines
1.2 KiB
Markdown
87 lines
1.2 KiB
Markdown
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# 字符、布尔、单元类型
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### 字符
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🌟
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```rust
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use std::mem::size_of_val;
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fn main() {
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let c1 = 'a';
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assert_eq!(size_of_val(&c1),1);
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let c2 = '中';
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assert_eq!(size_of_val(&c2),3);
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}
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```
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🌟
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```rust
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fn main() {
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let c1 = "中";
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print_char(c1);
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}
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fn print_char(c : char) {
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println!("{}", c);
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}
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```
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### 布尔
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🌟
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```rust
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// 让 println! 工作
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fn main() {
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let _f: bool = false;
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let t = true;
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if !t {
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println!("hello, world");
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}
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}
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```
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🌟
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```rust
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fn main() {
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let f = true;
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let t = true && false;
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assert_eq!(t, f);
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}
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```
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### 单元类型
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🌟🌟
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```rust
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// 让代码工作，但不要修改 `implicitly_ret_unit` !
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fn main() {
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let _v: () = ();
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let v = (2, 3);
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assert_eq!(v, implicitly_ret_unit())
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}
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fn implicitly_ret_unit() {
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println!("I will returen a ()")
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}
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// 不要使用下面的函数，它只用于演示！
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fn explicitly_ret_unit() -> () {
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println!("I will returen a ()")
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}
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```
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🌟🌟 单元类型占用的内存大小是多少？
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```rust
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// 让代码工作：修改 `assert!` 中的 `4`
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use std::mem::size_of_val;
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fn main() {
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let unit: () = ();
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assert!(size_of_val(&unit) == 4);
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}
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```
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