案例

下面的程式碼是我對官方案例作了簡單的修改而成。ActionChoices就是一個自定義的整型，當列舉數不夠多時，它預設的型別為uint8，當列舉數足夠多時，它會自動變成uint16，下面的GoLeft == 0,GoRight == 1, GoStraight == 2, SitStill == 3。在setGoStraight方法中，我們傳入的引數的值可以是0 - 3當傳入的值超出這個範圍時，就會中斷報錯

pragma solidity ^0.4.4;
contract test {
    enum ActionChoices { GoLeft, GoRight, GoStraight, SitStill }
 

    ActionChoices _choice;
    ActionChoices constant defaultChoice = ActionChoices.GoStraight;
    function setGoStraight(ActionChoices choice) public {
        _choice = choice;
    }
    function getChoice() constant public returns (ActionChoices) {
        return _choice;
    }
    function getDefaultChoice
 
() pure public returns (uint) {
        return uint(defaultChoice);
    }
}