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notes/代码可读性.md
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notes/代码可读性.md
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<!-- GFM-TOC -->
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* [<EFBFBD>ɶ<EFBFBD><EFBFBD>Ե<EFBFBD><EFBFBD><EFBFBD>Ҫ<EFBFBD><EFBFBD>](#<23>ɶ<EFBFBD><C9B6>Ե<EFBFBD><D4B5><EFBFBD>Ҫ<EFBFBD><D2AA>)
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* [<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ֱ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>뺬<EFBFBD><EFBFBD>](#<23><><EFBFBD><EFBFBD><EFBFBD>ֱ<EFBFBD><D6B1><EFBFBD><EFBFBD><EFBFBD><EFBFBD>뺬<EFBFBD><EBBAAC>)
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* [<EFBFBD><EFBFBD><EFBFBD>ֲ<EFBFBD><EFBFBD>ܴ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>](#<23><><EFBFBD>ֲ<EFBFBD><D6B2>ܴ<EFBFBD><DCB4><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>)
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* [<EFBFBD><EFBFBD><EFBFBD>õĴ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>](#<23><><EFBFBD>õĴ<C3B5><C4B4><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>)
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* [<EFBFBD><EFBFBD>дע<EFBFBD><EFBFBD>](#<23><>дע<D0B4><D7A2>)
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* [<EFBFBD><EFBFBD><EFBFBD>α<EFBFBD>дע<EFBFBD><EFBFBD>](#<23><><EFBFBD>α<EFBFBD>дע<D0B4><D7A2>)
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* [<EFBFBD><EFBFBD><EFBFBD>߿<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ŀɶ<EFBFBD><EFBFBD><EFBFBD>](#<23><><EFBFBD>߿<EFBFBD><DFBF><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ŀɶ<C4BF><C9B6><EFBFBD>)
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* [<EFBFBD><EFBFBD><EFBFBD>ֳ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʽ](#<23><><EFBFBD>ֳ<EFBFBD><D6B3><EFBFBD><EFBFBD><EFBFBD>ʽ)
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* [<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ɶ<EFBFBD><EFBFBD><EFBFBD>](#<23><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ɶ<EFBFBD><C9B6><EFBFBD>)
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* [<EFBFBD><EFBFBD>ȡ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>](#<23><>ȡ<EFBFBD><C8A1><EFBFBD><EFBFBD>)
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* [һ<EFBFBD><EFBFBD>ֻ<EFBFBD><EFBFBD>һ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>](#һ<><D2BB>ֻ<EFBFBD><D6BB>һ<EFBFBD><D2BB><EFBFBD><EFBFBD>)
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* [<EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ȼ<EFBFBD><EFBFBD><EFBFBD>Ա<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>](#<23><><EFBFBD><EFBFBD>Ȼ<EFBFBD><C8BB><EFBFBD>Ա<EFBFBD><D4B1><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>)
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* [<EFBFBD><EFBFBD><EFBFBD>ٴ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>](#<23><><EFBFBD>ٴ<EFBFBD><D9B4><EFBFBD><EFBFBD><EFBFBD>)
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* [可读性的重要性](#可读性的重要性)
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* [用名字表达代码含义](#用名字表达代码含义)
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* [名字不能带来歧义](#名字不能带来歧义)
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* [良好的代码风格](#良好的代码风格)
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* [编写注释](#编写注释)
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* [如何编写注释](#如何编写注释)
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* [提高控制流的可读性](#提高控制流的可读性)
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* [拆分长表达式](#拆分长表达式)
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* [变量与可读性](#变量与可读性)
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* [抽取函数](#抽取函数)
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* [一次只做一件事](#一次只做一件事)
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* [用自然语言表述代码](#用自然语言表述代码)
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* [减少代码量](#减少代码量)
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<!-- GFM-TOC -->
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# <20>ɶ<EFBFBD><C9B6>Ե<EFBFBD><D4B5><EFBFBD>Ҫ<EFBFBD><D2AA>
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>кܴ<EFBFBD>һ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʱ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ķ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>룬<EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ҫ<EFBFBD>Ķ<EFBFBD><EFBFBD>Լ<EFBFBD><EFBFBD>Ĵ<EFBFBD><EFBFBD>룬<EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ҫ<EFBFBD>Ķ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>˵Ĵ<EFBFBD><EFBFBD>롣<EFBFBD><EFBFBD><EFBFBD>ˣ<EFBFBD><EFBFBD>ɶ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>õĴ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>ܹ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>߱<EFBFBD><EFBFBD><EFBFBD>Ч<EFBFBD>ʡ<EFBFBD>
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# 可读性的重要性
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<EFBFBD>ɶ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>õĴ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ô<EFBFBD><EFBFBD><EFBFBD><EFBFBD>ܹ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>ã<EFBFBD><EFBFBD><EFBFBD>Ϊ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ա<EFBFBD><EFBFBD>Ը<EFBFBD><EFBFBD>ȥ<EFBFBD><EFBFBD><EFBFBD>ⲿ<EFBFBD>ִ<EFBFBD><EFBFBD>룬<EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ҳ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ġ<EFBFBD>
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编程有很大一部分时间是在阅读代码，不仅要阅读自己的代码，而且要阅读别人的代码。因此，可读性良好的代码能够大大提高编程效率。
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ֻ<EFBFBD><EFBFBD><EFBFBD>ں<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ϊ<EFBFBD><EFBFBD>Ч<EFBFBD>ʲſ<EFBFBD><EFBFBD>Է<EFBFBD><EFBFBD><EFBFBD><EFBFBD>ɶ<EFBFBD><EFBFBD>ԣ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ɶ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>ǵ<EFBFBD>һλ<EFBFBD><EFBFBD>
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可读性良好的代码往往会让代码架构更好，因为程序员更愿意去修改这部分代码，而且也更容易修改。
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# <20><><EFBFBD><EFBFBD><EFBFBD>ֱ<EFBFBD><D6B1><EFBFBD><EFBFBD><EFBFBD><EFBFBD>뺬<EFBFBD><EBBAAC>
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只有在核心领域为了效率才可以放弃可读性，否则可读性是第一位。
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һЩ<EFBFBD>Ƚ<EFBFBD><EFBFBD>б<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ĵ<EFBFBD><EFBFBD>ʣ<EFBFBD>
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# 用名字表达代码含义
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| <20><><EFBFBD><EFBFBD> | <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> |
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一些比较有表达力的单词：
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| 单词 | 可替代单词 |
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| --- | --- |
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| send | deliver<EFBFBD><EFBFBD>dispatch<EFBFBD><EFBFBD>announce<EFBFBD><EFBFBD>distribute<EFBFBD><EFBFBD>route |
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| find | search<EFBFBD><EFBFBD>extract<EFBFBD><EFBFBD>locate<EFBFBD><EFBFBD>recover |
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| start| launch<EFBFBD><EFBFBD>create<EFBFBD><EFBFBD>begin<EFBFBD><EFBFBD>open|
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| make | create<EFBFBD><EFBFBD>set up<EFBFBD><EFBFBD>build<EFBFBD><EFBFBD>generate<EFBFBD><EFBFBD>compose<EFBFBD><EFBFBD>add<EFBFBD><EFBFBD>new |
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| send | deliver、dispatch、announce、distribute、route |
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| find | search、extract、locate、recover |
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| start| launch、create、begin、open|
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| make | create、set up、build、generate、compose、add、new |
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ʹ<EFBFBD><EFBFBD> i<><69>j<EFBFBD><6A>k <20><>Ϊѭ<CEAA><D1AD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ֹ<EFBFBD><D6B9>ڼ<DABC>user_i<EFBFBD><EFBFBD>member_i <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ֻ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>б<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ϊѭ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Խ<EFBFBD>࣬<EFBFBD><EFBFBD><EFBFBD><EFBFBD>Խ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>⣬<EFBFBD>б<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ĵ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ֿɶ<EFBFBD><EFBFBD>Ի<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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使用 i、j、k 作为循环迭代器的名字过于简单，user_i、member_i 这种名字会更有表达力。因为循环层次越多，代码越难理解，有表达力的迭代器名字可读性会更高
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Ϊ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ݴʵ<EFBFBD><EFBFBD><EFBFBD>Ϣ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ָ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>б<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ҳ<EFBFBD><EFBFBD><EFBFBD>䳤<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ֳ<EFBFBD><EFBFBD>̵<EFBFBD><EFBFBD><EFBFBD><EFBFBD>ǣ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Խ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Խ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ֻ<EFBFBD><EFBFBD><EFBFBD>ڶ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʹ<EFBFBD><EFBFBD>һЩ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>֡<EFBFBD>
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为名字添加形容词等信息能让名字更具有表达力，但是名字也会变长。名字长短的准则是：作用域越大，名字越长。因此只有在短作用域才能使用一些简单名字。
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# <EFBFBD><EFBFBD><EFBFBD>ֲ<EFBFBD><EFBFBD>ܴ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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# 名字不能带来歧义
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ҫ˼<EFBFBD><EFBFBD>һ<EFBFBD>±<EFBFBD><EFBFBD>˻<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>кν<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ԭ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ĺ<EFBFBD><EFBFBD>塣
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起完名字要思考一下别人会对这个名字有何解读，会不会误解了原本想表达的含义。
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<EFBFBD><EFBFBD> min<EFBFBD><EFBFBD>max <EFBFBD><EFBFBD>ʾ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Χ<EFBFBD><EFBFBD><EFBFBD><EFBFBD> first<EFBFBD><EFBFBD>last <EFBFBD><EFBFBD>ʾ<EFBFBD><EFBFBD><EFBFBD>ʿռ<EFBFBD><EFBFBD>İ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Χ<EFBFBD><EFBFBD>begin<EFBFBD><EFBFBD>end <EFBFBD><EFBFBD>ʾ<EFBFBD><EFBFBD><EFBFBD>ʿռ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>ų<EFBFBD><EFBFBD><EFBFBD>Χ<EFBFBD><EFBFBD><EFBFBD><EFBFBD> end <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>β<EFBFBD><CEB2><EFBFBD><EFBFBD>
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用 min、max 表示数量范围；用 first、last 表示访问空间的包含范围，begin、end 表示访问空间的排除范围，即 end 不包含尾部。
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ص<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> is<EFBFBD><EFBFBD>can<EFBFBD><EFBFBD>should<EFBFBD><EFBFBD>has <EFBFBD><EFBFBD>ǰ<EFBFBD><EFBFBD>
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布尔相关的命名加上 is、can、should、has 等前缀。
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# <EFBFBD><EFBFBD><EFBFBD>õĴ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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# 良好的代码风格
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<EFBFBD>ʵ<EFBFBD><EFBFBD>Ŀ<EFBFBD><EFBFBD>к<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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适当的空行和缩进。
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ע<EFBFBD>ͣ<EFBFBD>
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排列整齐的注释：
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```
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int a = 1; // ע<EFBFBD><EFBFBD>
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int b = 11; // ע<EFBFBD><EFBFBD>
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int c = 111; // ע<EFBFBD><EFBFBD>
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int a = 1; // 注释
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int b = 11; // 注释
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int c = 111; // 注释
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```
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD>˳<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>⣬<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> html <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ı<EFBFBD><C4B1><EFBFBD><EFBFBD>ĸ<EFBFBD>ֵӦ<D6B5>úͱ<C3BA><CDB1><EFBFBD><EFBFBD><EFBFBD> html <20>е<EFBFBD>˳<EFBFBD><CBB3>һ<EFBFBD>£<EFBFBD>
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语句顺序不能随意，比如与 html 表单相关联的变量的赋值应该和表单在 html 中的顺序一致；
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>صĴ<EFBFBD><EFBFBD>밴<EFBFBD><EFBFBD><EFBFBD><EFBFBD>֯<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>һ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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把相关的代码按块组织起来放在一起。
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# <EFBFBD><EFBFBD>дע<EFBFBD><EFBFBD>
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# 编写注释
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<EFBFBD>Ķ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ȼ<EFBFBD>ע<EFBFBD>ע<EFBFBD>ͣ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ע<EFBFBD><EFBFBD>û̫<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ã<EFBFBD><EFBFBD><EFBFBD>ô<EFBFBD>ͻ<EFBFBD><EFBFBD>˷Ѵ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ķ<EFBFBD><EFBFBD><EFBFBD>ʱ<EFBFBD>䡣<EFBFBD><EFBFBD>Щ<EFBFBD><EFBFBD>ֱ<EFBFBD>ӿ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ĵ<EFBFBD><EFBFBD>벻<EFBFBD><EFBFBD>Ҫдע<EFBFBD>ͣ<EFBFBD><EFBFBD>ر<EFBFBD><EFBFBD>Dz<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ҪΪÿ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ע<EFBFBD>ͣ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Щ<EFBFBD><EFBFBD> getter <EFBFBD><EFBFBD> setter <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ϊ<EFBFBD><EFBFBD>Щ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>дע<EFBFBD>ͷ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>ô<EFBFBD><EFBFBD><EFBFBD><EFBFBD>ɶ<EFBFBD><EFBFBD>Ը<EFBFBD><EFBFBD>
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阅读代码首先会注意到注释，如果注释没太大作用，那么就会浪费代码阅读的时间。那些能直接看出含义的代码不需要写注释，特别是并不需要为每个方法都加上注释，比如那些简单的 getter 和 setter 方法，为这些方法写注释反而让代码可读性更差。
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ϊ<EFBFBD><EFBFBD>ע<EFBFBD>;<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>֣<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ȡ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ֶ<EFBFBD><EFBFBD><EFBFBD>дע<EFBFBD>͡<EFBFBD>
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不能因为有注释就随便起个名字，而是争取起个好名字而不写注释。
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ע<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>¼<EFBFBD><EFBFBD><EFBFBD>õ<EFBFBD>ǰ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>취<EFBFBD><EFBFBD>˼<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>̣<EFBFBD><EFBFBD>Ӷ<EFBFBD><EFBFBD>ö<EFBFBD><EFBFBD>߸<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>롣
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可以用注释来记录采用当前解决办法的思考过程，从而让读者更容易理解代码。
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ע<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>һЩ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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注释用来提醒一些特殊情况。
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<EFBFBD><EFBFBD> TODO <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ǣ<EFBFBD>
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用 TODO 等做标记：
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| <EFBFBD><EFBFBD><EFBFBD><EFBFBD> | <20>÷<EFBFBD> |
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| 标记 | 用法 |
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|---|---|
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|TODO| <EFBFBD><EFBFBD><EFBFBD><EFBFBD> |
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|FIXME| <EFBFBD><EFBFBD><EFBFBD><EFBFBD> |
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|HACH| <EFBFBD>ֲڵĽ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> |
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||||
|XXX| Σ<EFBFBD>գ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ҫ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> |
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|TODO| 待做 |
|
||||
|FIXME| 待修复 |
|
||||
|HACH| 粗糙的解决方案 |
|
||||
|XXX| 危险！这里有重要的问题 |
|
||||
|
||||
# <EFBFBD><EFBFBD><EFBFBD>α<EFBFBD>дע<EFBFBD><EFBFBD>
|
||||
# 如何编写注释
|
||||
|
||||
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ˣ<EFBFBD>
|
||||
尽量简洁明了：
|
||||
|
||||
```
|
||||
// The first String is student's name
|
||||
@ -97,7 +98,7 @@ Map<String, Integer> scoreMap = new HashMap<>();
|
||||
Map<String, Integer> scoreMap = new HashMap<>();
|
||||
```
|
||||
|
||||
<EFBFBD><EFBFBD><EFBFBD>Ӳ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>˵<EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||||
添加测试用例来说明：
|
||||
|
||||
```
|
||||
//...
|
||||
@ -107,7 +108,7 @@ int add(int x, int y) {
|
||||
}
|
||||
```
|
||||
|
||||
<EFBFBD>ںܸ<EFBFBD><EFBFBD>ӵĺ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ж<EFBFBD>ÿ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>֣<EFBFBD>
|
||||
在很复杂的函数调用中对每个参数标上名字：
|
||||
|
||||
```
|
||||
int a = 1;
|
||||
@ -115,37 +116,37 @@ int b = 2;
|
||||
int num = add(\* x = *\ a, \* y = *\ b);
|
||||
```
|
||||
|
||||
ʹ<EFBFBD><EFBFBD>רҵ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD≯<EFBFBD><EFBFBD><EFBFBD><EFBFBD>ϵĽ<EFBFBD><EFBFBD>ͣ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ģʽ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>˵<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>롣
|
||||
使用专业名词来缩短概念上的解释，比如用设计模式名来说明代码。
|
||||
|
||||
# <EFBFBD><EFBFBD><EFBFBD>߿<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ŀɶ<EFBFBD><EFBFBD><EFBFBD>
|
||||
# 提高控制流的可读性
|
||||
|
||||
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʽ<EFBFBD>У<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>DZ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ҳ<EFBFBD><EFBFBD>dz<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>һ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ȷ<EFBFBD><EFBFBD>
|
||||
条件表达式中，左侧是变量，右侧是常数。比如下面第一个语句正确：
|
||||
|
||||
```
|
||||
if(len < 10)
|
||||
if(10 > len)
|
||||
```
|
||||
|
||||
if / else <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>䣬<EFBFBD><EFBFBD><EFBFBD>Ĵ<EFBFBD><EFBFBD><EFBFBD>˳<EFBFBD><EFBFBD>Ϊ<EFBFBD><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD><DFBC><EFBFBD><EFBFBD><EFBFBD> <20>ؼ<EFBFBD><D8BC><EFBFBD><DFBC><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><DFBC><EFBFBD>
|
||||
if / else 条件语句，逻辑的处理顺序为：① 正逻辑；② 关键逻辑；③ 简单逻辑。
|
||||
```
|
||||
if(a == b) {
|
||||
// <EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||||
// 正逻辑
|
||||
} else{
|
||||
// <EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||||
// 反逻辑
|
||||
}
|
||||
```
|
||||
|
||||
ֻ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʹ<EFBFBD><EFBFBD> ? : <20><>Ŀ<EFBFBD><C4BF><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʹ<EFBFBD><CAB9><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>գ<EFBFBD><D5A3><EFBFBD><EFBFBD><EFBFBD>Ӧ<EFBFBD>ò<EFBFBD><C3B2>ֳ<EFBFBD> if / else<EFBFBD><EFBFBD>
|
||||
只有在逻辑简单的情况下使用 ? : 三目运算符来使代码更紧凑，否则应该拆分成 if / else；
|
||||
|
||||
do / while <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ں<EFBFBD><EFBFBD>棬<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ˣ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>һ<EFBFBD><EFBFBD><EFBFBD>һЩ<EFBFBD>Ի<EFBFBD><EFBFBD>ĵط<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʹ<EFBFBD><EFBFBD> while <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>档
|
||||
do / while 的条件放在后面，不够简单明了，并且会有一些迷惑的地方，最好使用 while 来代替。
|
||||
|
||||
<EFBFBD><EFBFBD><EFBFBD><EFBFBD>ֻ<EFBFBD><EFBFBD>һ<EFBFBD><EFBFBD> goto Ŀ<>꣬<EFBFBD><EAA3AC>ô goto <20><><EFBFBD>һ<EFBFBD><D2BB>ܽ<EFBFBD><DCBD>ܣ<EFBFBD><DCA3><EFBFBD><EFBFBD>ǹ<EFBFBD><C7B9>ڸ<EFBFBD><DAB8>ӵ<EFBFBD> goto <20><><EFBFBD>ô<EFBFBD><C3B4><EFBFBD><EFBFBD>ɶ<EFBFBD><C9B6><EFBFBD><EFBFBD>ر<EFBFBD><D8B1>Ӧ<EEA3AC>ñ<EFBFBD><C3B1><EFBFBD>ʹ<EFBFBD><CAB9> goto<EFBFBD><EFBFBD>
|
||||
如果只有一个 goto 目标，那么 goto 尚且还能接受，但是过于复杂的 goto 会让代码可读性特别差，应该避免使用 goto。
|
||||
|
||||
<EFBFBD><EFBFBD>Ƕ<EFBFBD><EFBFBD>ѭ<EFBFBD><EFBFBD><EFBFBD>У<EFBFBD><EFBFBD><EFBFBD>һЩ return <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ܼ<EFBFBD><DCBC><EFBFBD>Ƕ<EFBFBD>IJ<D7B5><C4B2><EFBFBD><EFBFBD><EFBFBD>
|
||||
在嵌套的循环中，用一些 return 语句往往能减少嵌套的层数。
|
||||
|
||||
# <EFBFBD><EFBFBD><EFBFBD>ֳ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʽ
|
||||
# 拆分长表达式
|
||||
|
||||
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʽ<EFBFBD>Ŀɶ<EFBFBD><EFBFBD>Ժܲ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>һЩ<EFBFBD><EFBFBD><EFBFBD>ͱ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ӷ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>ֱ<EFBFBD><EFBFBD><EFBFBD>ʽ<EFBFBD><EFBFBD>
|
||||
长表达式的可读性很差，可以引入一些解释变量从而拆分表达式：
|
||||
|
||||
```
|
||||
if line.split(':')[0].strip() == "root":
|
||||
@ -157,7 +158,7 @@ if username == "root":
|
||||
...
|
||||
```
|
||||
|
||||
ʹ<EFBFBD><EFBFBD>Ħ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>һЩ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʽ<EFBFBD><EFBFBD>
|
||||
使用摩根定理简化一些逻辑表达式：
|
||||
|
||||
```
|
||||
if(!a && !b) {
|
||||
@ -170,9 +171,9 @@ if(a || b) {
|
||||
}
|
||||
```
|
||||
|
||||
# <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ɶ<EFBFBD><EFBFBD><EFBFBD>
|
||||
# 变量与可读性
|
||||
|
||||
**ȥ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>**<EFBFBD><EFBFBD><EFBFBD><EFBFBD>ѭ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>ͨ<EFBFBD><EFBFBD>ʹ<EFBFBD><EFBFBD> break <EFBFBD><EFBFBD><EFBFBD><EFBFBD> return <EFBFBD><EFBFBD><EFBFBD>Լ<EFBFBD><EFBFBD>ٿ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʹ<EFBFBD>á<EFBFBD>
|
||||
**去除控制流变量**。在循环中通过使用 break 或者 return 可以减少控制流变量的使用。
|
||||
|
||||
```
|
||||
boolean done = false;
|
||||
@ -193,9 +194,9 @@ while(/* condition */) {
|
||||
}
|
||||
```
|
||||
|
||||
**<EFBFBD><EFBFBD>С<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>**<2A><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ԽС<D4BD><D0A1>Խ<EFBFBD><D4BD><EFBFBD><EFBFBD>λ<EFBFBD><CEBB><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʹ<EFBFBD>õĵط<C4B5><D8B7><EFBFBD>
|
||||
**减小变量作用域**。作用域越小，越容易定位到变量所有使用的地方。
|
||||
|
||||
JavaScript <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ñհ<EFBFBD><EFBFBD><EFBFBD>С<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>´<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> submit_form <20>Ǻ<EFBFBD><C7BA><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>submitted <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ƺ<EFBFBD><C6BA><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ᱻ<EFBFBD>ύ<EFBFBD><E1BDBB><EFBFBD>Ρ<EFBFBD><CEA1><EFBFBD>һ<EFBFBD><D2BB>ʵ<EFBFBD><CAB5><EFBFBD><EFBFBD> submitted <20><>ȫ<EFBFBD>ֱ<EFBFBD><D6B1><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ڶ<EFBFBD><DAB6><EFBFBD>ʵ<EFBFBD>ְ<EFBFBD> submitted <20>ŵ<EFBFBD><C5B5><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>У<EFBFBD><D0A3>Ӷ<EFBFBD><D3B6><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Χ<EFBFBD><CEA7>
|
||||
JavaScript 可以用闭包减小作用域。以下代码中 submit_form 是函数变量，submitted 变量控制函数不会被提交两次。第一个实现中 submitted 是全局变量，第二个实现把 submitted 放到匿名函数中，从而限制了起作用域范围。
|
||||
|
||||
```
|
||||
submitted = false;
|
||||
@ -216,16 +217,16 @@ var submit_form = (function() {
|
||||
}
|
||||
submitted = true;
|
||||
}
|
||||
}()); // () ʹ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ִ<EFBFBD><EFBFBD>
|
||||
}()); // () 使得外层匿名函数立即执行
|
||||
```
|
||||
|
||||
JavaScript <EFBFBD><EFBFBD>û<EFBFBD><EFBFBD><EFBFBD><EFBFBD> var <20><><EFBFBD><EFBFBD><EFBFBD>ı<EFBFBD><C4B1><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ȫ<EFBFBD>ֱ<EFBFBD><D6B1><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ȫ<EFBFBD>ֱ<EFBFBD><D6B1><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ի<EFBFBD><D4BB><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ӧ<EFBFBD><D3A6><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> var <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||||
JavaScript 中没有用 var 声明的变量都是全局变量，而全局变量很容易造成迷惑，因此应当总是用 var 来声明变量。
|
||||
|
||||
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>λ<EFBFBD><EFBFBD>Ӧ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʹ<EFBFBD>õ<EFBFBD>λ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||||
变量定义的位置应当离它使用的位置最近。
|
||||
|
||||
**ʵ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>**
|
||||
**实例解析**
|
||||
|
||||
<EFBFBD><EFBFBD>һ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>ҳ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ı<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ֶΣ<EFBFBD>
|
||||
在一个网页中有以下文本输入字段：
|
||||
|
||||
```
|
||||
<input type = "text" id = "input1" value = "a">
|
||||
@ -234,7 +235,7 @@ JavaScript
|
||||
<input type = "text" id = "input4" value = "d">
|
||||
```
|
||||
|
||||
<EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ҫ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>һ<EFBFBD><EFBFBD><EFBFBD>ַ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ŵ<EFBFBD><EFBFBD><EFBFBD>һ<EFBFBD><EFBFBD><EFBFBD>յ<EFBFBD> input <20>ֶ<EFBFBD><D6B6>У<EFBFBD><D0A3><EFBFBD>ʼʵ<CABC><CAB5><EFBFBD><EFBFBD><EFBFBD>£<EFBFBD>
|
||||
现在要接受一个字符串并把它放到第一个空的 input 字段中，初始实现如下：
|
||||
|
||||
```
|
||||
var setFirstEmptyInput = function(new_alue) {
|
||||
@ -254,11 +255,11 @@ var setFirstEmptyInput = function(new_alue) {
|
||||
}
|
||||
```
|
||||
|
||||
<EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʵ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>⣺
|
||||
以上实现有以下问题：
|
||||
|
||||
- found <EFBFBD><EFBFBD><EFBFBD><EFBFBD>ȥ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||||
- elem <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||||
- <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> for ѭ<><D1AD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> while ѭ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||||
- found 可以去除；
|
||||
- elem 作用域过大；
|
||||
- 可以用 for 循环代替 while 循环；
|
||||
|
||||
```
|
||||
var setFirstEmptyInput = function(new_value) {
|
||||
@ -275,13 +276,13 @@ var setFirstEmptyInput = function(new_value) {
|
||||
};
|
||||
```
|
||||
|
||||
# <EFBFBD><EFBFBD>ȡ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||||
# 抽取函数
|
||||
|
||||
<EFBFBD><EFBFBD><EFBFBD><EFBFBD>ѧ<EFBFBD><EFBFBD><EFBFBD>ǰѴ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ֳ<EFBFBD>С<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ٰ<EFBFBD><EFBFBD><EFBFBD>Щ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ľ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ż<EFBFBD>һ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||||
工程学就是把大问题拆分成小问题再把这些问题的解决方案放回一起。
|
||||
|
||||
<EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ӧ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>ȷһ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ĸ߲<EFBFBD><EFBFBD><EFBFBD>Ŀ<EFBFBD>꣬Ȼ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ڲ<EFBFBD><EFBFBD><EFBFBD>ֱ<EFBFBD><EFBFBD>Ϊ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ŀ<EFBFBD>깤<EFBFBD><EFBFBD><EFBFBD>Ĵ<EFBFBD><EFBFBD>룬<EFBFBD><EFBFBD>ȡ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ŵ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ĺ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>С<EFBFBD>
|
||||
首先应该明确一个函数的高层次目标，然后对于不是直接为了这个目标工作的代码，抽取出来放到独立的函数中。
|
||||
|
||||
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ԵĴ<EFBFBD><EFBFBD>룺
|
||||
介绍性的代码：
|
||||
|
||||
```
|
||||
int findClostElement(int[] arr) {
|
||||
@ -302,7 +303,7 @@ int findClostElement(int[] arr) {
|
||||
}
|
||||
```
|
||||
|
||||
<EFBFBD><EFBFBD><EFBFBD>ϴ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ѭ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ҫ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>룬<EFBFBD>ⲿ<EFBFBD>ֲ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>ڴ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>߲<EFBFBD><EFBFBD><EFBFBD>Ŀ<EFBFBD>꣬<EFBFBD>߲<EFBFBD><EFBFBD><EFBFBD>Ŀ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ѱ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>С<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ֵ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>˿<EFBFBD><EFBFBD><EFBFBD><EFBFBD>ⲿ<EFBFBD>ִ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ȡ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ĺ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>С<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ҳ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>һ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ĺô<EFBFBD><EFBFBD>У<EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ե<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>в<EFBFBD><EFBFBD>ԡ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>Կ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>ҵ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ġ<EFBFBD>
|
||||
以上代码中循环部分主要计算距离，这部分不属于代码高层次目标，高层次目标是寻找最小距离的值，因此可以把这部分代替提取到独立的函数中。这样做也带来一个额外的好处有：可以单独进行测试、可以快速找到程序错误并修改。
|
||||
|
||||
```
|
||||
public int findClostElement(int[] arr) {
|
||||
@ -319,22 +320,22 @@ public int findClostElement(int[] arr) {
|
||||
}
|
||||
```
|
||||
|
||||
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ǻ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ȡ<EFBFBD><EFBFBD>Խ<EFBFBD><EFBFBD>Խ<EFBFBD>ã<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ȡ<EFBFBD><EFBFBD><EFBFBD>࣬<EFBFBD><EFBFBD><EFBFBD>Ķ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʱ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ҫ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ȥ<EFBFBD><EFBFBD>ֻ<EFBFBD><EFBFBD><EFBFBD>ڵ<EFBFBD>ǰ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ҫȥ<EFBFBD>˽<EFBFBD>ijһ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ϸ<EFBFBD>ڶ<EFBFBD><EFBFBD>ܹ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʱ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ȡ<EFBFBD><EFBFBD><EFBFBD>Ӻ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ǻõġ<EFBFBD>
|
||||
并不是函数抽取的越多越好，如果抽取过多，在阅读代码的时候可能需要不断跳来跳去。只有在当前函数不需要去了解某一块代码细节而能够表达其内容时，把这块代码抽取成子函数才是好的。
|
||||
|
||||
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ȡҲ<EFBFBD><EFBFBD><EFBFBD>ڼ<EFBFBD>С<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ࡣ
|
||||
函数抽取也用于减小代码的冗余。
|
||||
|
||||
# һ<EFBFBD><EFBFBD>ֻ<EFBFBD><EFBFBD>һ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||||
# 一次只做一件事
|
||||
|
||||
ֻ<EFBFBD><EFBFBD>һ<EFBFBD><EFBFBD><EFBFBD>µĴ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>֪<EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ҫ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>£<EFBFBD>
|
||||
只做一件事的代码很容易让人知道其要做的事；
|
||||
|
||||
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>̣<EFBFBD><EFBFBD>г<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ÿ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ֵ<EFBFBD><EFBFBD><EFBFBD>ͬ<EFBFBD>ĺ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>߲<EFBFBD>ͬ<EFBFBD>Ķ<EFBFBD><EFBFBD>䡣
|
||||
基本流程：列出代码所做的所有任务；把每个任务拆分到不同的函数，或者不同的段落。
|
||||
|
||||
# <EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ȼ<EFBFBD><EFBFBD><EFBFBD>Ա<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||||
# 用自然语言表述代码
|
||||
|
||||
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ȼ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>д<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ҳ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>α<EFBFBD><EFBFBD><EFBFBD>룬Ȼ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>д<EFBFBD><EFBFBD><EFBFBD>룬<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||||
先用自然语言书写代码逻辑，也就是伪代码，然后再写代码，这样代码逻辑会更清晰。
|
||||
|
||||
# <EFBFBD><EFBFBD><EFBFBD>ٴ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||||
# 减少代码量
|
||||
|
||||
<EFBFBD><EFBFBD>Ҫ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ƣ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>̻<EFBFBD><EFBFBD>кܶ<EFBFBD><EFBFBD>仯<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ƶ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>ݵ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>õġ<EFBFBD>
|
||||
不要过度设计，编码过程会有很多变化，过度设计的内容到最后往往是无用的。
|
||||
|
||||
<EFBFBD><EFBFBD><EFBFBD>ñ<EFBFBD><EFBFBD><EFBFBD>ʵ<EFBFBD>֡<EFBFBD>
|
||||
多用标准库实现。
|
||||
|
||||
Reference in New Issue
Block a user