Anonymous user
Constrained random points on a circle: Difference between revisions
Constrained random points on a circle (view source)
Revision as of 23:27, 26 January 2018
, 6 years ago→{{header|Rust}}: add Rust solution
(→{{header|Rust}}: add Rust solution) |
|||
Line 3,014:
render #g
#g "flush"</lang>
=={{header|Rust}}==
<lang Rust>#![feature(inclusive_range_syntax)]
extern crate rand;
use rand::Rng;
const POINTS_N: usize = 100;
fn generate_point<R: Rng>(rng: &mut R) -> (i32, i32) {
loop {
let x = rng.gen_range(-15, 16); // exclusive
let y = rng.gen_range(-15, 16);
let r2 = x * x + y * y;
if r2 >= 100 && r2 <= 225 {
return (x, y);
}
}
}
fn filtering_method<R: Rng>(rng: &mut R) {
let mut rows = [[" "; 62]; 31];
// Generate points
for _ in 0..POINTS_N {
let (x, y) = generate_point(rng);
rows[(y + 15) as usize][(x + 15) as usize * 2] = "*";
}
// draw the points
for row in &rows {
println!("{}", row.concat());
}
}
fn precalculating_method<R: Rng>(rng: &mut R) {
// Generate all possible points
let mut possible_points = Vec::with_capacity(404);
for y in -15..=15 {
for x in -15..=15 {
let r2 = x * x + y * y;
if r2 >= 100 && r2 <= 225 {
possible_points.push((x, y));
}
}
}
// A truncated Fisher-Yates shuffle
let len = possible_points.len();
for i in (len - POINTS_N..len).rev() {
let j = rng.gen_range(0, i + 1);
possible_points.swap(i, j);
}
// turn the selected points into "pixels"
let mut rows = [[" "; 62]; 31];
for &(x, y) in &possible_points[len - POINTS_N..] {
rows[(y + 15) as usize][(x + 15) as usize * 2] = "*";
}
// draw the "pixels"
for row in &rows {
println!("{}", row.concat());
}
}
fn main() {
let mut rng = rand::weak_rng();
filtering_method(&mut rng);
precalculating_method(&mut rng);
}</lang>
=={{header|Scala}}==
| |||