Rust学习笔记（1） Rust学习笔记（1）

内容整理自：https://doc.rust-lang.org/book/title-page.html
Chapter 1

check rust version

rust —version

How to run a rust program

fn main() { println!("hello world"); }

main function is the entry to run in every app
! means it runs a macro instead of a function
2 steps to run: compile and run
- pros: run everywhere even without rust installed
- cons: 2 steps
- just a design tradeoff

Cargo

What is cargo
- build system
- package manager
already installed with rust
check cargo version
cargo —version
Creating a project with Cargo
cargo new hello_cargo
packages of code are referred to as crates
build with cargo
cargo build
run
./target/build/hello_cargo
Or
cargo run
check package doc
cargo doc --open
quickly checks your code to make sure it compiles but doesn’t produce an executable
cargo check
Faster than cargo build, can be used as check your work
release
cargo build --release
Build with optimizations, in target/release

Chapter 2 guessing game

variables

let foo = 5; // immutable let mut bar = 5; // mutable

storing variables

io::stdin().read_line(&mut guess) .expect("Failed to read line");

【Rust学习笔记（1）】The & indicates that this argument is a reference, which gives you a way to let multiple parts of your code access one piece of data without needing to copy that data into memory multiple times.

Handling Potential Failure with the Result Type
io::stdin().read_line(&mut guess).expect("Failed to read line");
The Result types are enumerations, often referred to as enums. An enumeration is a type that can have a fixed set of values, and those values are called the enum’s variants
print values
println!("You guessed: {}", guess);
{} is a placeholder