Hello, World!

Direct Compilation

Create main.rs:

fn main() {
    println!("Hello, world!");
}

Compile and run:

$ rustc main.rs
$ ./main                    # Linux/macOS
$ .\main.exe               # Windows

Program Structure

fn main() {                 // Entry point (like main() in C)
    println!("Hello, world!");  // Macro call (note the !)
}

Key differences from TypeScript/Node.js:

  • Ahead-of-time compilation: Unlike Node.js’s JIT, Rust compiles to native binaries
  • Macros: println! is a macro (indicated by !), not a function
  • No runtime: Unlike Node.js, compiled binaries run without a runtime environment

Compilation Model

Unlike interpreted languages (JavaScript) or VM languages with JIT (Java), Rust uses ahead-of-time compilation:

  1. Source → Binary: Direct compilation to machine code
  2. Zero dependencies: Binaries run without Rust installation
  3. Static linking: All dependencies bundled in the executable

This is similar to Go’s compilation model but with stronger memory safety guarantees.

For larger projects, use Cargo instead of direct rustc compilation.