Hello World
Hello, World!
fn main() {
println!("Hello, world!");
}
fn
means function. main function is the beginning of every Rust program.
println!
prints text to the console and its ! indicate that it’s a macro instead of a function.
💡 Rust files should have .rs file extension and if you’re using more than one word for the file name, follow the snake_case.
Save above code in
file.rs
, but it can be any name with.rs
extension.Compiling via
rustc file.rs
Executing by
./file
on Linux and Mac orfile.exe
on Windows
Rust Playground
Rust Playground is a web interface for running Rust code.

Usages of println!
💯 These are the other usages of println! macro,
fn main() {
println!("{}, {}!", "Hello", "world"); // Hello, world!
println!("{0}, {1}!", "Hello", "world"); // Hello, world!
println!("{greeting}, {name}!", greeting="Hello", name="world"); // Hello, world!
println!("{:?}", [1,2,3]); // [1, 2, 3]
println!("{:#?}", [1,2,3]);
/*
[
1,
2,
3
]
*/
// 🔎 format! macro is used to store the formatted STRING
let x = format!("{}, {}!", "Hello", "world");
println!("{}", x); // Hello, world!
}
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