Variables In println!

The code from the prior page includes this line:

println!("alfa is {alfa}");

which produced this output:

alfa is 7

The characters first piece of text quoted inside println!() is called a "format string". Format strings can output basic text like we saw with the original println!("Hello, World") example. They can also output the value of variables like we're doing with alfa above.

The process works by adding {} curly brackets with the name of the variable inside it. In our case this is:

{alfa}

Here's another example where we set the variable bravo to 12 then print it out.

fn main() {
  let bravo = 12;
  println!("bravo is {bravo}");
}