rust学习(二)

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match if

 #![allow(unused)]

 fn write_bar(size: u64){

     match size{

         o if o <  => println!("{:?} less than 100", o),

         o if o <  && o >   => println!("{:?} between 100-200", o),

         _ => println!("{:?} bigger than 200", size),

     }

 }

 fn main() {

     write_bar();

     write_bar();

     write_bar();

 }

println!("{:#?}", 1)

 #[derive(Debug)]

 struct Teacher<'a> {

     name: &'a str,

     age1: u8

 }

 #[derive(Debug)]

 struct Person<'a> {

     name: &'a str,

     age: u8

 }

 fn main() {

     let name = "Peter";

     let mut age = ;

     let peter = Person { name, age };

     age = ;

     let lilei = Teacher{ name:"Lilei", age1:age};

     // 美化打印

     println!("{:#?}", lilei);

     println!("{:#?}", peter);

 }

println! with param

 #[derive(Debug)]

 struct Complex { real: f32, imag: f32 }

 fn main() {

     println!("The big range is {big:#?} and the small is {small}",

              small = ,

              big = &[, ]);

     println!("Debug: {:#?}", Complex{real: 2.2, imag: 7.2});

 }

try! 宏和 ? 一样

write!(f, "{}", value)?;

try!(write!(f, "{}", value));

闭包

|val| val + x，　输入和返回类型两者都可以自动推导，而输入变量 名必须指明。

• 声明时使用 || 替代 () 将输入参数括起来。
• 函数体定界符（{}）对于单个表达式是可选的，其他情况必须加上。
• 有能力捕获外部环境的变量。

fn function (i: i32) -> i32 { i + 1 }

let closure_annotated = |i: i32| -> i32 { i + 1 };

　　

valgrind 也可以检查rust的内存泄露

Drop trait 包含在 prelude 中，所以无需导入它。