Create Project
- Use cargo new exercise to create a new exercise/ directory for your code:
(base) [yanboyang713@archlinux ~]$ cargo new exercise
Created binary (application) `exercise` package- Navigate into exercise/ and use cargo run to build and run your binary:
(base) [yanboyang713@archlinux ~]$ cd exercise/
(base) [yanboyang713@archlinux exercise]$ cargo run
Compiling exercise v0.1.0 (/home/yanboyang713/exercise)
Finished dev [unoptimized + debuginfo] target(s) in 0.33s
Running `target/debug/exercise`
Hello, world!- Replace the boiler-plate code in src/main.rs with your own code. For example, using the example on the previous page, make src/main.rs look like
fn main() {
println!("Edit me!");
}- Use cargo run to build and run your updated binary:
(base) [yanboyang713@archlinux exercise]$ cargo run
Compiling exercise v0.1.0 (/home/yanboyang713/exercise)
Finished dev [unoptimized + debuginfo] target(s) in 0.33s
Running `target/debug/exercise`
Edit me!- Use cargo check to quickly check your project for errors, use cargo build to compile it without running it. You will find the output in target/debug/ for a normal debug build. Use cargo build —release to produce an optimized release build in target/release/. NOTE: You can add dependencies for your project by editing Cargo.toml. When you run cargo commands, it will automatically download and compile missing dependencies for you.
Hello World
Let us jump into the simplest possible Rust program, a classic Hello World program:
fn main() {
println!("Hello 🌍!");
}What you see:
- Functions are introduced with fn.
- Blocks are delimited by curly braces like in C and C++.
- The main function is the entry point of the program.
- Rust has hygienic macros, println! is an example of this.
- Rust strings are UTF-8 encoded and can contain any Unicode character.
language characteristic
- Rust is very much like other languages in the C/C++/Java tradition. It is imperative and it doesn’t try to reinvent things unless absolutely necessary.
- Rust is modern with full support for things like Unicode.
- Rust uses macros for situations where you want to have a variable number of arguments (no Function Overloading).
- Macros being ‘hygienic’ means they don’t accidentally capture identifiers from the scope they are used in. Rust macros are actually only partially hygienic.
- Rust is multi-paradigm. For example, it has powerful Object-Oriented Programming Features, and, while it is not a functional language, it includes a range of Functional Language Features.