rust基础

赋值:let i = 1;

返回:不需要写return,直接不加;就是return x了
fn add_one(x: i32) -> i32 {
    x + 1
}

mut 标记为变量

if的使用
let x = 5;

if x == 5 {
    println!("x is five!");
} else if x == 6 {
    println!("x is six!");
} else {
    println!("x is not five or six ");
}

loop死循环
loop {
    println!("Loop forever!");
}

while循环
fn do_while() {
    while true {
        println!("a")
    }
}

for循环
fn test_for(){
    for x in 0..10 {
        println!("{}", x); // x: i32
    }
}

数组:
fn test_arr2(i:usize) {
    let v = vec![1, 2, 3];
    match v.get(i) {
        Some(x) => println!("Item 7 is {}", x),
        None => println!("Sorry, this vector is too short.")
    }
    //遍历
    for i in &v {
        println!("A reference to {}", i);
    }
}

test_arr2(2); //Item 7 is 3
test_arr2(7); //Sorry, this vector is too short.

A reference to 1
A reference to 2
A reference to 3