# 控制结构：if-else if-else是我们熟知的一种控制结构。Lua 跟其他语言一样，提供了if-else的控制结构。因为是大家熟悉的语法，本节只简单介绍一下它的使用方法。 #### 单个 if 分支 型 ~~~ x = 10 if x > 0 then print("x is a positive number") end ~~~ > 运行输出：x is a positive number #### 两个分支： if-else 型 ~~~ x = 10 if x > 0 then print("x is a positive number") else print("x is a non-positive number") end ~~~ > 运行输出：x is a positive number #### 多个分支： if-elseif-else型 ~~~ score = 90 if score == 100 then print("Very good!Your score is 100") elseif score >= 60 then print("Congratulations, you have passed it,your score greater or equal to 60") --此处可以添加多个elseif else print("Sorry, you do not pass the exam! ") end ~~~ > 运行输出：Congratulations, you have passed it,your score greater or equal to 60 与C语言的不同之处是elseif是连在一起的，若不else与if写成"else if"则相当于在else 里嵌套,如下代码： ~~~ score = 0 if score == 100 then print("Very good!Your score is 100") elseif score >= 60 then print("Congratulations, you have passed it,your score greater or equal to 60") else if score > 0 then print("Your score is better than 0") else print("My God, your score turned out to be 0") end --与上一示例代码不同的是，此处要添加一个end end ~~~ > 运行输出：My God, your score turned out to be 0