Using the Standard library

• std

• f32

• f64

• consts

• PI

• std

fn main() {
    println!("{}", std::f32::consts::PI);
    println!("{}", std::f64::consts::PI);

    // println!("{}", PI); // error[E0425]: cannot find value `PI` in this scope
}

3.1415927
3.141592653589793