game of life - section 2

gol2.go

package main

import (
	"fmt"
	"math/rand"
	"time"
)

type World struct {
	Width  int
	Height int
	Cells  [][]*Cell
}

func (w *World) String() (s string) {
	for _, row := range w.Cells {
		s += fmt.Sprintf("%s\n", row)
	}
	return
}

func NewWorld(width int, height int) (w *World) {
	w = &World{
		Height: height,
		Width:  width,
		Cells:  make([][]*Cell, width),
	}

	for x := 0; x < w.Width; x++ {
		w.Cells[x] = make([]*Cell, height)
	}
	return w
}

func (w *World) GetNeighbors(c *Cell) (neighbors []*Cell) {
	neighbors = []*Cell{}
	for x := c.PositionX - 1; x < c.PositionX+2 && x < w.Width; x++ {
		// log.Println("x", x)
		if x == -1 {
			continue
		}
	innerLoop:
		for y := c.PositionY - 1; y < c.PositionY+2 && y < w.Height; y++ {
			// log.Println("y", y)
			if y == -1 {
				continue innerLoop
			}
			if x != c.PositionX || y != c.PositionY {
				// log.Println("ADD", x, y)
				neighbors = append(neighbors, w.Cells[x][y])
			}
		}
	}
	// fmt.Println("==", c.PositionX, c.PositionY, neighbors)
	return
}

func (w *World) Initialize() {
	rand.Seed(time.Now().UnixNano())
	for x := 0; x < w.Width; x++ {
		for y := 0; y < w.Height; y++ {
			w.Cells[x][y] = &Cell{
				PositionX: x,
				PositionY: y,
			}
			r := rand.Intn(9)
			if r >= 7 {
				w.Cells[x][y].Alive = true
			}
		}
	}
}

func (w *World) NextGeneration() (newWorld *World) {
	newWorld = NewWorld(w.Width, w.Height)
	for x := 0; x < w.Width; x++ {
		for y := 0; y < w.Height; y++ {
			newWorld.Cells[x][y] = w.Cells[x][y].NextGeneration()
		}
	}
	return
}

type Cell struct {
	PositionX int
	PositionY int
	Alive     bool
}

func (c *Cell) String() string {
	if c.Alive {
		return "😊" // "😊"
	}
	return "　" // "😲"
}

func (c *Cell) NextGeneration() (nc *Cell) {
	var aliveCount int = 0
	// fmt.Println("==", c.PositionX, c.PositionY, TheWorld.GetNeighbors(c))
	for _, neighborCell := range TheWorld.GetNeighbors(c) {
		if neighborCell.Alive {
			aliveCount++
		}
	}

	nc = &Cell{
		PositionX: c.PositionX,
		PositionY: c.PositionY,
	}

	if c.Alive {
		nc.Alive = (aliveCount == 2 || aliveCount == 3)
	} else {
		nc.Alive = (aliveCount == 3)
	}
	return
}

var (
	TheWorld *World
)

func main() {
	TheWorld = NewWorld(10, 10)
	TheWorld.Initialize()
	fmt.Println(TheWorld)
	for i := 0; i < 100; i++ {
		TheWorld = TheWorld.NextGeneration()
		time.Sleep(100 * time.Millisecond)
		fmt.Println(TheWorld)
	}
}