procedural programming

functional programming

object-oriented programming

高级 state machine 抽象

例如：旋转栅门

$输入 = {coin，turn，none}$输入=coin，turn，none
$输出 = {enter，pay}$输出=enter，pay
$状态 = {locked，unlocked}$状态=locked，unlocked

$nextState(s,i)=\begin{cases} unlocked, & i = coin \\ locked, & i = turn \\ s, & otherwise \end{cases}$nextState(s,i)=⎩⎪⎨⎪⎧​unlocked,locked,s,​i=coini=turnotherwise​

$output(s,i)=\begin{cases} enter, & if\ nextState(s,i) = unlocked\\ pay, & otherwise \end{cases}$output(s,i)={enter,pay,​if nextState(s,i)=unlockedotherwise​

• 结点表示状态
• 弧线表示状态转换条件