下载了一本书，练练。

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一，代码

static G1: i32 = 3;

type Age = u32;

fn grow(age: Age, year: u32) -> Age {
    age + year
}

fn main() {
    /*
    println!("Hello, world!");
    println!("{}", 1);
    println!("{:o}", 9);
    println!("{:x}", 255);
    println!("{:X}", 255);
    println!("{:p}", &0);
    println!("{:b}", 15);
    println!("{:e}", 10000f32);
    println!("{:E}", 10000f32);
    println!("{:?}", "test");
    println!("{:#?}", ("test1", "test2"));
    println!("{a} {b} {b}", a = "x", b = "y");
    let _variable: i32 = 100;
    let x = 5;
    x = 10;
    let mut x = 5;
    x = 10;
    let (mut a, mut b) = (1, 2);
    let x = "hello";
    println!("x is {}", x);
    let x = 5;
    println!("x is {}", x);
    let mut v = Vec::new();
    v.push(1);
    v.push(2);
    v.push(3);

    let v = v;
    for i in &v {
        println!("{}", i);
    }
    let elem = 5u8;
    let mut vec = Vec::new();
    vec.push(elem);
    println!("{:?}", vec);
    let player_scores = [
        ("Jack", 20), ("Jane", 23), ("Jill", 18), ("John", 19),
    ];

    let players:Vec<_> = player_scores
        .iter()
        .map(|&(player, _score)| {
            player
        })
        .collect();
    println!("{:?}", players);*/
    let x: Age = 20;
    println!("20 year later: {}", grow(x, 20));
    println!("{}", G1);
}

二，截图

C:/Users/ccc/.cargo/bin/cargo.exe run --color=always --package first_rust --bin first_rust
   Compiling first_rust v0.1.0 (D:\tmp\first_rust)
    Finished dev [unoptimized + debuginfo] target(s) in 0.48s
     Running `target\debug\first_rust.exe`
20 year later: 40
3

Process finished with exit code 0

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