turtles-own [energy] ;; 須要給turtles新建一個屬性 to setup clear-all ask patches[ if random-float 1 < 0.2[ set pcolor green ;;隨機長草 ] ] create-turtles 1[ set energy 100 ;;給個初始化的能量值 ] reset-ticks end to go add_food ;; 每一步都要讓草長出來 ask turtles[ turtle_move ;; 函數調用 turtle_breed turtle_die ] tick end to add_food ;; 長草=添加食物 ask n-of 10 patches[ ;; 隨機取出10個patch set pcolor green ] end to turtle_move ;; 移動 if pcolor = green [ set energy energy + 10 ;; 吃草 set pcolor black ] if random-float 1 < 0.2 [ set heading random 360 ;; 有必定的機率隨機改變方向 ] set energy energy - 1 ;;每走一步,能量減小 fd 1 ;;向前移動 end to turtle_breed ;; 繁殖 if energy > 500[ set energy energy - 450 hatch 1[ ;; 生育出一頭小羊 fd 1 set energy 100 ;; 小羊的初始能量 ] ] end to turtle_die ;; 沒能量就死亡 if energy <= 0 [ die ] end