03.hello_ rust

first Rust Program .

1. Create a directory first hello_rust.
2. You can use handy editing （jetbrains Series can be installed rust plug-in unit , Or is it vscode Of rust All plug-ins are OK ）.
3. establish rust Source code file , It is to use .rs As an extension .
4. stay hello.rs in , Input

fn main(){
   println!("Hello Rust!")
}

Copy

fn - Rust Language use fn Keywords define functions .main() Function is a predefined main function , act as Rust The entry point of the program , Every language has its own main() function . println!() yes Rust One of the languages Predefined macros . It is used to output the parameters passed to it to standard output .

notes ：Rust In language macro with Exclamatory mark ( ! ) ending . See later with ! Similar function calls at the end , All are Macro call .Rust Provides a very powerful macro system , Through these macro , We can do it easily Metaprogramming .Rust Medium macro It's kind of like function . Can be macro Understood as a Enhanced version of function .

Use rustc hello.rs, Compile a to hello Binary executable with name

function ./hello, Screen output Hello Rust!