Final Program Tutorial 3

turtles-own [energy]     ;; for keeping track of when the turtle is ready
                         ;; to reproduce and when it will die

to setup
  clear-all
  setup-patches
  setup-turtles
  reset-ticks
end 

to setup-patches
  ask patches [ set pcolor green ]
end 

to setup-turtles
  create-turtles number       ;; uses the value of the number slider to create turtles
  ask turtles [ setxy random-xcor random-ycor ]
end 

to go
  if ticks >= number-of-ticks [ stop ]  ;; stop after user defined # of ticks
  if not any? turtles [ stop ]      ;; stops if number of turtles reaches 0
  move-turtles
  eat-grass
  check-depth
  reproduce
  regrow-grass
  tick      ;; increase the tick counter by 1 each time through
end 

to move-turtles
  ask turtles [
    right random 360
    forward 1
    set energy energy - energy-to-move     ;; when the turtle moves it looses the user defined amount of energy
  ]
end 

to eat-grass
  ask turtles [
    if pcolor = green [
      set pcolor black       ;; the value of birth-energy slider is added to energy
      set energy birth-energy
    ]
    ifelse show-energy?
      [ set label energy ]      ;; the label is set to be the value of the energy
      [ set label "" ]          ;; the label is set to an empty text value
  ]
end 

to reproduce
  ask turtles [
    if energy > birth-energy [
      set energy energy - birth-energy      ;; take away birth-energy to give birt
      hatch 1 [ set energy birth-energy ]   ;; give this birth-energy to the offspring
    ]
  ]
end 

to check-depth
  ask turtles [
    if energy <= 0 [ die ]      ;; removes the turtle if it has no energy left
  ]
end 

to regrow-grass
  ask patches [
    if random 100 < grass-regrowth-rate [ set pcolor green ]      ;; each patch has a random chance of growing grass
  ]                                                               ;; based on the grass-regrowth-rate set by user
end