game_of_life.go

package main

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

const (
    width = 80
    height = 15
)

type Universe [][]bool

func NewUniverse() (result Universe) {
    result = make([][]bool, height)
    for i, _ := range result {
        result[i] = make([]bool, width)
    }
    
    return
}

func (u Universe) Seed() {
    // Seed approximately 25% of each row
    var count int = width / 4
    for i := range u {
        for j := 0; j <= count; j++ {
            u[i][rand.Intn(width)] = true
        }
    }
}

func (u Universe) Show() {
    for _, row := range u {
        for _, alive := range row {
            if alive {
                fmt.Print("*")
            } else {
                fmt.Print(" ")
            }
        }
        
        fmt.Println()
    }
}

func (u Universe) Alive(x, y int) bool {
    // x part
    for x < 0 {
        x += width
    }
    if x >= width {
        x = x % width
    }

    // y part
    for y < 0 {
        y += height
    }
    if y >= height {
        y = y % height
    }

    return u[y][x]
}

func (u Universe) Neighbors(x, y int) (count int) {
    for i := x - 1; i < x + 2; i++ {
        for j := y - 1; j < y + 2; j++ {
            if (i != x || j != y) && u.Alive(i, j) {
                count++
            }
        }
    }

    return
}

func (u Universe) Next(x, y int) bool {
    neighbors := u.Neighbors(x, y)
    if u.Alive(x, y) {
        return neighbors == 3 || neighbors == 2
    } else {
        return neighbors == 3
    }
}

func Step(a, b Universe) {
    for i, row := range a {
        for j, _ := range row {
            b[i][j] = a.Next(j, i)
        }
    }
}

func main() {
    u := NewUniverse()
    u.Seed()

    m := NewUniverse()
    
    for {
        fmt.Println("\033[H")
        u.Show()
        Step(u, m)
        u, m = m, u
        time.Sleep(1 * time.Second / 10)
    }
}