// returns a distance between two boids
returns a distance between two boids
returns a distance between two boids
fn distance_to(&self, b: &Boid) -> f64 {
        let x = self.x - b.x;
        let y = self.y - b.y;
        (x*x + y*y).sqrt()
    }
fn distance_to ( & self , b : & Boid ) -> f64 { let x = self . x - b . x ; let y = self . y - b . y ; ( x * x + y * y ) . sqrt ( ) }
returns a distance between two boids
returns a distance between two boids
&self
b
&Boid