Deal cards for FreeCell: Difference between revisions

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 Based on JavaScript.
+<lang rust>// Code available at https://rosettacode.org/wiki/Linear_congruential_generator#Rust
-<lang rust>
+extern crate linear_congruential_generator;
-struct MSVCRandGen {
-    seed: u32
+use linear_congruential_generator::{MsLcg, Rng, SeedableRng};
-}
+// We can't use `rand::Rng::shuffle` because it uses the more uniform `rand::Rng::gen_range`
-impl MSVCRandGen {
+// (`% range` is subject to modulo bias).  If an exact match of the old dealer is not needed,
-    fn rand(&mut self) -> u32 {
+// `rand::Rng::shuffle` should be used.
-        self.seed = (self.seed.wrapping_mul(214013).wrapping_add(2531011)) % 0x80000000;
+fn shuffle<T>(rng: &mut MsLcg, deck: &mut [T]) {
-        assert!(self.seed >> 16 < 32768);
-        (self.seed >> 16) & 0x7FFF
+    let len = deck.len() as u32;
+    for i in (1..len).rev() {
-    }
+        let j = rng.next_u32() % (i + 1);
-    fn max_rand(&mut self, mymax: u32) -> u32 {
-        self.rand() % mymax
+        deck.swap(i as usize, j as usize);
-    }
-    fn shuffle<T>(&mut self, deck: &mut [T]) {
-        if deck.len() > 0 {
-            let mut i = (deck.len() as u32) - 1;
-            while i > 0 {
-                let j = self.max_rand(i+1);
-                deck.swap(i as usize, j as usize);
-                i = i-1;
-            }
-        }
     }
 }
-fn deal_ms_fc_board(seed: u32) -> String {
+fn gen_deck() -> Vec<String> {
+    const RANKS: [char; 13] = ['A','2','3','4','5','6','7','8','9','T','J','Q','K'];
-    let mut randomizer = MSVCRandGen { seed: seed, };
+    const SUITS: [char; 4] = ['C', 'D', 'H', 'S'];
-    let num_cols = 8;
-    let mut columns = vec![Vec::new(); num_cols];
+    let render_card = |card: usize| {
+        let (suit, rank) = (card % 4, card / 4);
-    let mut deck: Vec<_> = (0..4*13).collect();
+        format!("{}{}", RANKS[rank], SUITS[suit])
+    };
-    let rank_strings: Vec<char> = "A23456789TJQK".chars().collect();
+    (0..52).map(render_card).collect()
+}
-    let suit_strings: Vec<char> = "CDHS".chars().collect();
+fn deal_ms_fc_board(seed: u32) -> Vec<String> {
-    randomizer.shuffle(&mut deck);
+    let mut rng = MsLcg::from_seed(seed);
+    let mut deck = gen_deck();
+    shuffle(&mut rng, &mut deck);
     deck.reverse();
+    deck.chunks(8).map(|row| row.join(" ")).collect::<Vec<_>>()
-    for i in 0..52 {
+}
-        columns[i % num_cols].push(deck[i]);
-    }
+fn main() {
-    let render_card = |card: usize| -> String {
-        let (suit, rank) = (card % 4, card / 4);
+    let seed = std::env::args()
+        .nth(1)
-        format!("{}{}", rank_strings[rank], suit_strings[suit])
+        .and_then(|n| n.parse().ok())
-    };
+        .expect("A 32-bit seed is required");
+    for row in deal_ms_fc_board(seed) {
-    let render_column = |col: Vec<usize>| -> String {
+        println!(": {}", row);
-        format!(": {}\n", col.into_iter().map(&render_card).collect::<Vec<String>>().join(" "))
-    };
+    }
-    columns.into_iter().map(render_column).collect::<Vec<_>>().join("")
 }
+</lang>
-fn main() {
-    let arg: u32 = std::env::args().nth(1).and_then(|n| n.parse().ok()).expect("I need a number.");
-    print!("{}", deal_ms_fc_board(arg));
-}</lang>
 =={{header|Seed7}}==