Closure

A closure is an anonymous function that can capture variables from its surrounding environment.

fn main() {
    let pi: f32 = 3.14;
    
    // Single line closure.
    let area = |x: f32| pi * x * x;
    
    let n: f32 = 10.0;
    let result = area(n);
    
    println!("Area of cicle: {}", result);
}