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Small fixes and use min/max

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This commit is contained in:
Jon Fetter-Degges
2022-10-11 22:03:57 -04:00
parent 5214f2a681
commit 7b929ecbb1
2 changed files with 19 additions and 25 deletions
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43
55_Life/rust/src/main.rs
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@@ -5,7 +5,7 @@
// I am a Rust newbie. Corrections and suggestions are welcome.
use std::{fmt, io, thread, time};
use std::{cmp, fmt, io, thread, time};
const HEIGHT: usize = 24;
const WIDTH: usize = 70;
@@ -42,9 +42,8 @@ impl fmt::Display for CellState {
}
// Following the BASIC implementation, we will bound the board at 24 rows x 70 columns.
// Since that isn't too big (even in the 70's), we just store the whole board as an
// array of CellState. I'm experimenting with using an array-of-arrays to make references
// more convenient.
// The board is an array of CellState. Using an array of arrays gives us bounds checking
// in both dimensions.
struct Board {
cells: [[CellState; WIDTH]; HEIGHT],
min_row: usize,
@@ -145,12 +144,13 @@ fn parse_pattern(rows: Vec<Vec<char>>) -> Board {
board.max_row = board.min_row + nrows - 1;
board.max_col = board.min_col + ncols - 1;
// Loop over the rows provided. The enumerate() method augments the iterator with an index.
// Loop over the rows provided. enumerate() augments the iterator with an index.
for (row_index, pattern) in rows.iter().enumerate() {
let row = board.min_row + row_index;
// Now loop over the non-empty cells in the current row. filter_map takes a closure that
// returns an Option. If the Option is None, filter_map filters out that entry from the
// for loop. If it's Some(x), filter_map executes the loop body with the value x.
// Now loop over the non-empty cells in the current row. filter_map takes a
// closure that returns an Option. If the Option is None, filter_map filters out
// that entry from the for loop. If it's Some(x), filter_map executes the loop
// body with the value x.
for col in pattern.iter().enumerate().filter_map(|(col_index, chr)| {
if *chr == ' ' || (*chr == '.' && col_index == 0) {
None
@@ -186,22 +186,14 @@ fn finish_cell_transitions(board: &mut Board) {
}
if *cell == CellState::Alive {
any_alive_this_row = true;
if min_col > col_index {
min_col = col_index;
}
if max_col < col_index {
max_col = col_index;
}
min_col = cmp::min(min_col, col_index);
max_col = cmp::max(max_col, col_index);
}
}
if any_alive_this_row {
if min_row > row_index {
min_row = row_index;
}
if max_row < row_index {
max_row = row_index;
}
}
min_row = cmp::min(min_row, row_index);
max_row = cmp::max(max_row, row_index);
}
}
// If anything is alive within two cells of the boundary, mark the board invalid and
// clamp the bounds. We need a two-cell margin because we'll count neighbors on cells
@@ -232,14 +224,14 @@ fn finish_cell_transitions(board: &mut Board) {
fn print_board(board: &Board) {
println!(); println!(); println!();
print!("Generation: {} Population: {}", board.generation, board.population);
print!("Generation: {} Population: {}", board.generation, board.population);
if board.invalid {
print!("Invalid!");
print!(" Invalid!");
}
println!();
for row_index in 0..HEIGHT {
for col_index in 0..WIDTH {
// This print will use the Display implementation for cell_state, above.
// This print uses the Display implementation for cell_state, above.
print!("{}", board.cells[row_index][col_index]);
}
println!();
@@ -268,7 +260,8 @@ fn mark_cell_transitions(board: &mut Board) {
for row_index in board.min_row-1..=board.max_row+1 {
for col_index in board.min_col-1..=board.max_col+1 {
let neighbors = count_neighbors(board, row_index, col_index);
let this_cell_state = &mut board.cells[row_index][col_index]; // borrow a mutable reference to the array cell
// Borrow a mutable reference to the array cell
let this_cell_state = &mut board.cells[row_index][col_index];
*this_cell_state = match *this_cell_state {
CellState::Empty if neighbors == 3 => CellState::AboutToBeBorn,
CellState::Alive if !(2..=3).contains(&neighbors) => CellState::AboutToDie,