https://doc.rust-lang.org/book/ rustup doc --book # https://github.com/rust-lang/rustup/issues/2980 Notes: 1 getting started cargo is optional for using rust. it provides for reproducible builds from versioned dependencies using Cargo.lock . hello_cargo: # or write the other two files by hand cargo new hello_cargo cd hello_cargo Cargo.toml: [package] name = "hello_cargo" version = "0.1.0" edition = "2021" [dependencies] src/main.rs: fn main() { println!("Hello, world!"); } rustc src/main.rs # compile by hand cargo check # verify syntax cargo build # compile with cargo cargo run # executes target/debug/hello_cargo cargo run will automatically build cargo build will automatically pass --release to build to target/release Most rust projects out there will build with "cargo build". 2 guessing game src/main.rs: use std::io; fn main() { println!("Guess the number!"); println!("Please input your guess."); let mut guess = String::new(); io::stdin() .read_line(&mut guess) .expect("Failed to read line"); println!("You guessed: {}", guess); } global things like println! and String are listed at https://doc.rust-lang.org/std/prelude/index.html std::io provides io::stdin and its read_line member locally. These are always accessible globally with std::io::stdin. constants and mutables: let apples = 5; // immutable let mut bananas = 5; // mutable String::new is a static or associated function of the string type. It creates a new String. in read_line(&mut guess), & specifies to pass guess by reference rather than value, and mut specifies to let read_line mutate it functions in rust often return Results, enums of either Ok or Err that can have type members and associated data. io::Result has a .expect member function that either raises the passed error text for Err, or returns the associated data for Ok. rust emits warnings for unhandled Results. Cargo.toml: [package] name = "guessing_game" version = "0.1.0" edition = "2021" # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html [dependencies] rand = "0.8.3" diff -u main.rs.old main.rs: --- main.rs.old 2022-04-24 04:40:47.371994619 -0400 +++ main.rs 2022-04-24 04:40:01.011994637 -0400 @@ -1,8 +1,13 @@ use std::io; +use rand::Rng; fn main() { println!("Guess the number!"); + let secret_number = rand::thread_rng().gen_range(1..101); + + println!("The secret number is: {}", secret_number); + println!("Please input your guess."); let mut guess = String::new(); rand::Rng adds random number generator traits. without it, gen_range() does not appear on thread_rng(). rand::thread_rng() is a thread local OS-seeded prng. 1..101 is a range expression of [1,101). it is equivalent here to 1..100 which is [1,100]. cargo doc --open will show documentation of the rand and all other project crates. use rand::Rng; use std::cmp::Ordering; use std::io; fn main() { println!("Guess the number!"); let secret_number = rand::thread_rng().gen_range(1..101); loop { println!("Please input your guess."); let mut guess = String::new(); io::stdin() .read_line(&mut guess) .expect("Failed to read line"); let guess: u32 = match guess.trim().parse() { Ok(num) => num, Err(_) => continue, }; println!("You guessed: {}", guess); match guess.cmp(&secret_number) { Ordering::Less => println!("Too small!"), Ordering::Greater => println!("Too big!"), Ordering::Equal => { println!("You win!"); break; } } } } rust lets you shadow variables in the same scope, retyping them, optionally based on their previous values String::trim removes the enter character read_line preserved String::parse returns a number match {} is a switch or select statement that provides for patterns and use as an expression rust infers the type of secret_number from the type of guess std::cmp::Ordering is an enum type return by the .cmp method. Homework: 1. Implement and run the guessing example. 2. Make a rust project that uses std::io to generate a .jl julia script that performs and outputs the result of an arithmetic calculation. file output: https://doc.rust-lang.org/stable/std/io/ julia: see other thread with similar name