【rust】rust基础代码案例

代码篇

HelloWorld

fn main() {
    print!("Hello,Wolrd")
}

斐波那契数列

fn fib(n: u64) -> u64 {
    let mut a = 0;
    let mut b = 1;
    for _ in 0..n {
        let c = a + b;
        a = b;
        b = c;
    }
    a
}

fn main() {
    let n = 10;
    let result_list: Vec<String> = (1..n+1).map(|i| fib(i).to_string()).collect();
    let result = result_list.join(",");
    println!("{}", result);
}

计算表达式（加减乘除）

use std::io;
use std::num::ParseIntError;
fn parse_expression(expression: &str) -> Result<i32, ParseIntError> {
    let mut result = 0;
    let mut current_number = 0;
    let mut operator = '+';

    for token in expression.split_whitespace() {
        match token {
            "+" => operator = '+',
            "-" => operator = '-',
            "*" => operator = '*',
            "/" => operator = '/',
            _ => {
                current_number = match token.parse::<i32>() {
                    Ok(num) => num,
                    Err(e) => return Err(e),
                };
                match operator {
                    '+' => result += current_number,
                    '-' => result -= current_number,
                    '*' => result *= current_number,
                    '/' => result /= current_number,
                    _ => {},
                }
            }
        }
    }

    Ok(result)
}
fn main() {
    println!("请输入表达式（例如：1 + 2 * 3）：");
    let mut input = String::new();
    io::stdin().read_line(&mut input).expect("读取输入失败");
    let expression = input.trim();
    match parse_expression(expression) {
        Ok(result) => println!("计算结果为：{}", result),
        Err(e) => println!("解析表达式时出错：{}", e),
    }
}

web接口

use actix_web::{get, post, web, App, HttpResponse, HttpServer, Responder};

#[get("/")]
async fn hello() -> impl Responder {
    HttpResponse::Ok().body("Hello world!")
}

#[post("/echo")]
async fn echo(req_body: String) -> impl Responder {
    HttpResponse::Ok().body(req_body)
}

async fn manual_hello() -> impl Responder {
    HttpResponse::Ok().body("Hey there!")
}

#[actix_web::main]
async fn main() -> std::io::Result<()> {
    HttpServer::new(|| {
        App::new()
            .service(hello)
            .service(echo)
            .route("/hey", web::get().to(manual_hello))
    })
    .bind(("127.0.0.1", 8080))?
    .run()
    .await
}

优化篇

target/目录占用一个g，仅仅一个actix的helloWorld demo

~/.cargo/config写入, 放到项目之外去，眼不见心不烦

[build]
target-dir = "/path/rust-target"

不过一个demo 接口， 你执行下cargo run 和 cargo build --release, 就占用1.2g。 这可真烧磁盘, 有node_module那味儿了。

升级rust版本， 通过rustup

export RUSTUP_DIST_SERVER="https://rsproxy.cn"
export RUSTUP_UPDATE_ROOT="https://rsproxy.cn/rustup"
rustup update

cargo换源

~/.cargo/config写入

[source.crates-io]
registry = "https://github.com/rust-lang/crates.io-index"
replace-with = 'ustc'
[source.ustc]
registry = "https://mirrors.ustc.edu.cn/crates.io-index/"

windows下放弃吧，需要额外安装1g的toolchain并且要配合msvc（10g起步吧）或者mingw。

比linux下的工具链大多了

原文地址：https://blog.csdn.net/2301_76933862/article/details/143490108

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