1.基础语法

Arr

rust

let arr = [1,2,3];
let arr:[i32;3] = [1,2,3];
let arr = [3;5];   //arr = [3,3,3,3,3];

Tuple

rust

let tuple = ('A','1','1.2');
let tuple:(i32,f64,u8) = (500,16.4,1);
let hand = tuple.0;
let(x,y,z) = tup //=>x=tup.0,y=tup.1,z=tup.2

2.函数

主函数

rust

fn main()
{
}

函数

rust

fn name(a:i32,b:char)
{
    println!("the message is {a}{b}");
}

表达式

rust

fn main()
{
    let y = {
        let x = 3;
        x + 1
    };// {}内为表达式 y只获得最终结果
}

返回值

rust

fn five()->i32{ //->后跟返回值
    5 //没;
    //或者 return 5;  有;
}

if表达式

rust

fn main()
{
    let a:i32 = 3;
    if a < 5 
    {
        println!("小于5");
    }
    else if a == 5
    {
        println!("等于5");
    }
    else 
    {
        println!("大于5");
    }
}

循环表达

loop

1.作为结果值返回

rust

fn main() {
    let mut temp = 0;
    let a = loop
    {
        temp+=1;
        if temp == 10
        {
            break temp * 2;
        }
    };
}

2.作为while(1)用

rust

fn main(){
    let mut a = 0;
    loop{
        a+=1;
        if a == 10{
            break;
        }
    }
}

3.小goto

rust

fn main(){
    let mut count = 0;
    'counting_up:loop{//把这个loop打上标签
        println!("count = {count}");
        let mut remaining = 10;

        loop{
            println!("remaining = {remaining}");
            if remaining == 9{
                break;
            }
            if count == 2{
                break 'counting_up;//用标签的方式结束
            }
            remaining -= 1;
        }
        count += 1;
    }
    println!("End count = {count}");
} //直接跳到外层循环

while

rust

while a == true{}// 和py 一毛一样

for

rust

for value in arr{} //和py 一毛一样
//对于for循环循环n次一般这样表示
for number in (1..4){}
//循环三次 1 2 3 左闭右开区间