How to reimplement a class with sets instead of arrays in Swift - ios

Question

I am trying to redevelop the Colony class I wrote for Conway's Game of Life with Sets instead of arrays but am having trouble doing so. Here's what I've got so far:
P.S. I am assuming a fixed Colony size of 20x20.
import Foundation
struct Array2DB {
var values: [Int]
var rows: Int
var cols: Int
init(rows: Int, cols: Int){
self.rows = rows
self.cols = cols
values = [Int](repeating: 0, count: (rows + 2) * (cols + 2) )
}
//allows uasge of the syntax [row, col] for get/set access
subscript(row:Int, col: Int) -> Int {
get {
return values[getIndex(row, col)]
}
set(val) {
values[getIndex(row, col)] = val
}
}
//converts 2D indices to index in data (terminates if out of bounds)
func getIndex(_ row: Int, _ col: Int) -> Int {
assert((row >= -1) && (row <= rows), "row \(row) is out of bounds")
assert((col >= -1) && (col <= cols), "col \(col) is out of bounds")
return (row + 1) * cols + col + 1
}
var description: String {
var desc = "Matrix:\n"
for row in 0 ..< rows {
for col in 0 ..< cols {
desc += " \(values[getIndex(row, col)]) "
}
desc += "\n"
}
return desc
}
}
class Colony: CustomStringConvertible {
let colony: Set = Array2DB[rows, cols, values]
func setCellAlive(xCoor: Int, yCoor: Int) {
colony[xCoor, yCoor] = 1
}
func setCellDead(xCoor:Int, yCoor: Int) {
colony[xCoor, yCoor] = 0
}
func resetColony() {
for i in 0..<colony.rows {
for e in 0..<colony.cols {
colony[i, e] = 0
}
}
}
var description: String {
var desc = ""
for i in 0..<colony.rows {
for e in 0..<colony.cols {
if colony[i, e] == 1 {
desc += "*"
} else {
desc += "-"
}
}
desc += "\n"
}
return desc
}
func isCellALive( xCoor: Int, yCoor: Int) -> Bool{
return colony[xCoor, yCoor] == 1
}
func evolve() {
var colonyUpdate: Array2DB = colony
for i in 0..<colony.rows {
for e in 0..<colony.cols {
let cGen = rules(xCoor: i, yCoor: e)
if ((cGen < 2) || (cGen > 3)) {
colonyUpdate[i, e] = 0
} else if cGen == 3 {
colonyUpdate[i, e] = 1
} else {
if colony[i, e] == 1 {
colonyUpdate[i, e] = 1
} else {
colonyUpdate[i, e] = 0
}
}
}
}
colony = colonyUpdate
}
}
I'm sure that I've implemented it wrong, but how would I turn the arrays to sets? I'm really confused and would appreciate any guidance or feedbac

Answer 1

Your data type Array2DB is not an Array. It is a Struct that contains an array. You can't assign an Array2DB to a variable that you've declared to be of type Set. It won't work.
You also can't use a Set as the storage for Conway's game of life. The Swift Set data type is an unordered collection. It is unsuitable to serve as the storage for the data in the game of life. You want an array, period.

Answer 2

A very little help for you to show an example of using Set in Game of Life.
struct Cell: Hashable {
var x: Int
var y: Int
}
class Colony: CustomStringConvertible {
var aliveCells: Set = Set<Cell>()
let numberOfRows: Int
let numberOfColumns: Int
init(colonySize: Int) {
self.numberOfRows = colonySize
self.numberOfColumns = colonySize
}
func setCellAlive(xCoor: Int, yCoor: Int) {
aliveCells.insert(Cell(x: xCoor, y: yCoor))
}
func setCellDead(xCoor:Int, yCoor: Int) {
aliveCells.remove(Cell(x: xCoor, y: yCoor))
}
func resetColony() {
aliveCells.removeAll(keepingCapacity: true)
}
var description: String {
var desc = ""
for i in 0..<numberOfRows {
for e in 0..<numberOfColumns {
if aliveCells.contains(Cell(x: e, y: i)) { //Usually `x` represents column, and `y` for row
desc += "*"
} else {
desc += "-"
}
}
desc += "\n"
}
return desc
}
//Implement other methods you need
//...
}
As already noted, Set is not a good data type for Game of Life. But you can implement it using Set. Good luck.