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。