Galton box animation: Difference between revisions
Added Go
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Link to live demo: http://dc25.github.io/galtonBoxAnimationElm/ . Follow the link, enter a number and press the GO button.
=={{header|Go}}==
{{trans|D}}
<lang go>package main
import (
"fmt"
"math/rand"
"time"
)
const boxW = 41 // Galton box width
const boxH = 37 // Galton box height.
const pinsBaseW = 19 // Pins triangle base.
const nMaxBalls = 55 // Number of balls.
const centerH = pinsBaseW + (boxW-pinsBaseW*2+1)/2 - 1
const (
empty = ' '
ball = 'o'
wall = '|'
corner = '+'
floor = '-'
pin = '.'
)
type Ball struct{ x, y int }
func newBall(x, y int) *Ball {
if box[y][x] != empty {
panic("Tried to create a new ball in a non-empty cell. Program terminated.")
}
b := Ball{x, y}
box[y][x] = ball
return &b
}
func (b *Ball) doStep() {
if b.y <= 0 {
return // Reached the bottom of the box.
}
cell := box[b.y-1][b.x]
switch cell {
case empty:
box[b.y][b.x] = empty
b.y--
box[b.y][b.x] = ball
case pin:
box[b.y][b.x] = empty
b.y--
if box[b.y][b.x-1] == empty && box[b.y][b.x+1] == empty {
b.x += rand.Intn(2)*2 - 1
box[b.y][b.x] = ball
return
} else if box[b.y][b.x-1] == empty {
b.x++
} else {
b.x--
}
box[b.y][b.x] = ball
default:
// It's frozen - it always piles on other balls.
}
}
type Cell = byte
/* Galton box. Will be printed upside down. */
var box [boxH][boxW]Cell
func initializeBox() {
// Set ceiling and floor
box[0][0] = corner
box[0][boxW-1] = corner
for i := 1; i < boxW-1; i++ {
box[0][i] = floor
}
for i := 0; i < boxW; i++ {
box[boxH-1][i] = box[0][i]
}
// Set walls
for r := 1; r < boxH-1; r++ {
box[r][0] = wall
box[r][boxW-1] = wall
}
// Set rest to empty initially
for i := 1; i < boxH-1; i++ {
for j := 1; j < boxW-1; j++ {
box[i][j] = empty
}
}
// Set pins
for nPins := 1; nPins <= pinsBaseW; nPins++ {
for p := 0; p < nPins; p++ {
box[boxH-2-nPins][centerH+1-nPins+p*2] = pin
}
}
}
func drawBox() {
for r := boxH - 1; r >= 0; r-- {
for c := 0; c < boxW; c++ {
fmt.Printf("%c", box[r][c])
}
fmt.Println()
}
}
func main() {
rand.Seed(time.Now().UnixNano())
initializeBox()
var balls []*Ball
for i := 0; i < nMaxBalls+boxH; i++ {
fmt.Println("\nStep", i, ":")
if i < nMaxBalls {
balls = append(balls, newBall(centerH, boxH-2)) // add ball
}
drawBox()
// Next step for the simulation.
// Frozen balls are kept in balls slice for simplicity
for _, b := range balls {
b.doStep()
}
}
}</lang>
{{out}}
Sample output (showing last step only):
<pre>
Step 91 :
+---------------------------------------+
| |
| . |
| . . |
| . . . |
| . . . . |
| . . . . . |
| . . . . . . |
| . . . . . . . |
| . . . . . . . . |
| . . . . . . . . . |
| . . . . . . . . . . |
| . . . . . . . . . . . |
| . . . . . . . . . . . . |
| . . . . . . . . . . . . . |
| . . . . . . . . . . . . . . |
| . . . . . . . . . . . . . . . |
| . . . . . . . . . . . . . . . . |
| . . . . . . . . . . . . . . . . . |
| . . . . . . . . . . . . . . . . . . |
| . . . . . . . . . . . . . . . . . . . |
| |
| |
| o |
| o |
| o o |
| o o |
| o o |
| o o o |
| o o o |
| o o o o o |
| o o o o o |
| o o o o o o o |
| o o o o o o o |
| o o o o o o o o |
| o o o o o o o o o |
+---------------------------------------+
</pre>
=={{header|Haskell}}==
| |||