├── LICENSE └── README.md /LICENSE: -------------------------------------------------------------------------------- 1 | GNU GENERAL PUBLIC LICENSE 2 | Version 2, June 1991 3 | 4 | Copyright (C) 1989, 1991 Free Software Foundation, Inc., 5 | 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 6 | Everyone is permitted to copy and distribute verbatim copies 7 | of this license document, but changing it is not allowed. 8 | 9 | Preamble 10 | 11 | The licenses for most software are designed to take away your 12 | freedom to share and change it. By contrast, the GNU General Public 13 | License is intended to guarantee your freedom to share and change free 14 | software--to make sure the software is free for all its users. This 15 | General Public License applies to most of the Free Software 16 | Foundation's software and to any other program whose authors commit to 17 | using it. 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If this is what you want to do, use the GNU Lesser General 339 | Public License instead of this License. -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | 后端开发面试题 2 | ================ 3 | 4 | ## 说明 5 | 6 | 这篇文章翻译自一位外国友人的关于面试后端程序员的文章，我比较喜爱这篇文章。一是因为它极大的拓宽了我的视角，另一方面是其中的一些问题非常具有启发性。不仅对于面试者，对于面试官来说也是个不错的参考。于是迫不及待的翻译了一下，给各位看官做个参考。 7 | 8 | 这篇文章中，许多问题我并没有完全理解，所以翻译可能存在不准确的地方。如果有读者发现有一些翻译有误或者不好的地方，请不吝赐教。 9 | 10 | 原文参见 [@arialdomartini](https://github.com/arialdomartini)的: [Back-End Developer Interview Questions](https://github.com/arialdomartini/Back-End-Developer-Interview-Questions) 11 | 12 | 以下是原文翻译。 13 | 14 | 后端开发面试题 15 | ================ 16 | 17 | 在面试的时候，我并不特别喜欢问一些技术性的问题。我更喜欢的方式是这样的: 和面试者坐在一起，看一些实际的代码，解决一些实际的问题。并且用一整天的时间，让团队所有成员轮流和面试者进行结对编程。虽然如此，但是一些技术问题仍然可以用来很好地启动一段有深度的谈话，能够让面试者和面试官相互都有更加深入的了解。 18 | 19 | 这个仓库包含了可以用来考核面试者的一系列后端面试题。但绝不是说，面试官必须用每个面试题来考核面试者（这样可能要耗费好几个小时）。根据你期望面试者拥有的技能，从这个列表中有选择的挑一些题目，可以帮助你在特定技能上考核面试者。 20 | 21 | 应当承认的是，这个项目的灵感来自于[@darcyclarke](https://github.com/darcyclarke)的文章[Front-end Job Interview Questions](https://github.com/darcyclarke/Front-end-Developer-Interview-Questions) 22 | 23 | **注意:** 请记住，这些面试题中有许多问题是开放式的，能引导讨论一些有趣的问题。相比那些有直接答案的问题来说，这种问题能够让你对面试者的能力有更多的了解。再一次强调，我认为仅仅是问问题是不够的。要通过与面试者较长时间的结对编程来完成面试: 这是你们相互了解对方的风格和方法、让面试者了解未来工作的最佳手段之一。 24 | 25 | ## 目录 26 | 27 | 1. [通用问题](#general) 28 | 1. [开放式问题](#open) 29 | 1. [设计模式相关问题](#patterns) 30 | 1. [代码设计相关问题](#design) 31 | 1. [语言相关问题](#languages) 32 | 1. [Web相关问题](#web) 33 | 1. [数据库相关问题](#databases) 34 | 1. [非关系型数据库相关问题](#nosql) 35 | 1. [代码版本管理相关问题](#codeversioning) 36 | 1. [并发问题](#concurrency) 37 | 1. [分布式系统相关问题](#distributed) 38 | 1. [软件生命周期和团队管理相关问题](#management) 39 | 1. [逻辑和算法相关问题](#algorithms) 40 | 1. [软件架构相关问题](#architecture) 41 | 1. [面向服务架构(SOA)和微服务(Microservice)相关问题](#soa) 42 | 1. [安全相关问题](#security) 43 | 1. [比尔盖茨式问题](#billgates) 44 | 1. [代码示例问题](#snippets) 45 | 46 | #### 通用问题: [[↑]](#toc) 47 | 48 | * 语言设计中空引用([null reference](http://programmers.stackexchange.com/questions/12777/are-null-references-really-a-bad-thing))的存在有什么问题？假设你想要将空引用的概念从你的首选语言中移除，可能导致什么结果？ 49 | * 为什么函数式编程重要？什么时候适用函数式语言？ 50 | * 设计(design)、架构(architecture)、功能(functionality)和美学(aesthetic)之间有什么区别？讨论一下。 51 | * 微软、谷歌、欧朋(opera)和火狐这类公司是如何从他们的浏览器中获利的？ 52 | * 为什么打开TCP套接字有很大的开销？ 53 | * 封装的重要性体现在哪儿？ 54 | * 什么是实时系统？它与普通系统有什么区别？ 55 | * 实时语言(real-time language)和堆内存分配(heap memory allocation)之间的关系是什么？ 56 | * 不变性(Immutability)是指: (变量的)值只能在创建的时候被设置一次，之后就不能被改变。为什么不变性对写更加安全的代码有帮助？ 57 | * 可变值(mutable values)和不可变值(immutable values)有哪些优缺点？ 58 | * 什么是O/R阻抗失衡(Object-Relational impedence mismatch)？ 59 | * 如果你需要使用缓存，你使用哪些原则来确定缓存的大小？ 60 | * TCP和HTTP有什么区别？ 61 | * 在客户端渲染(client-side rendering)和服务端渲染(server-side rendering)之间，你是如何权衡的？ 62 | * 如何在一个不可靠的协议之上构建一个可靠的通信协议？ 63 | 64 | #### 开放式问题: [[↑]](#toc) 65 | 66 | * 为什么人们会抵制变化？ 67 | * 如何向你的祖母解释什么是线程？ 68 | * 作为一个软件工程师，你想要既要有创新力，又要产出具有可预测性。采用什么策略才能使这两个目标可以共存呢？ 69 | * 什么是好的代码？ 70 | * 解释什么是流(Streaming)和如何实现一个流？ 71 | * 假设你的公司给你一周的时间，用来改善你和同事的生活: 你将如何使用这一周？ 72 | * 本周你学了什么？ 73 | * 所有的设计中都会有美学元素(aesthetic element)的存在。问题是，你认为美学元素是你的朋友还是敌人？ 74 | * 列出最近你读过的5本书。 75 | * 假设目前有个大型公司（非常有钱），他们的开发流程是瀑布式流程（Waterfall），如果需要你在他们公司引入持续交付（[Continue Devivery](https://en.wikipedia.org/wiki/Continuous_delivery)），你会怎么做？ 76 | * 我们来谈谈"*重复造轮子*","*非我发明症*", "*吃自己做出来的狗粮*"的这些做法吧。 77 | 78 | (注: 重复造轮子: Reinventing the wheel; 非我发明症:Not Invented Here Syndrome; 吃自己做出来的狗粮: Eating Your Own Dog Food) 79 | 80 | * 在你当前的工作流中，什么事情是你计划下一步需要自动化的？ 81 | * 为什么写软件是困难的？是什么使软件的维护变得困难？ 82 | * 你更喜欢在全新项目（Green Field Project）上工作还是在已有项目(Brown Field Project)基础上工作？为什么？ 83 | * [当你在浏览器地址栏输入google.com回车之后都发生了什么?](https://github.com/alex/what-happens-when) 84 | * 当操作系统CPU处于空闲的时候，它可能在处理哪些事情？ 85 | * 如何向一个5岁的孩子解释什么是Unicode/数据库事务？ 86 | * 如何维护单体架构(monolithic architecture)？ 87 | * 一个"专业的开发者"意味着什么？ 88 | * 软件开发是艺术、是技艺还是工程？你的观点是什么？ 89 | * "喜欢这个的人也喜欢..."，如何在一个电子商务商店里实现这种功能？ 90 | * 为什么在创新上，企业会比创业公司慢些？ 91 | * 为什么说，对于涉及密码学的问题，你不应该尝试应用自己的发明或者设计？ 92 | 93 | #### 设计模式相关问题: [[↑]](#toc) 94 | 95 | * 请用一个例子表明，全局对象是邪恶的存在。 96 | * 假设你工作的系统不支持事务性，你会如何从头开始实现它？ 97 | * 什么是好莱坞原则（Hollywood Principles）？ 98 | * 关于迪米特法则(最少知识原则): 写一段代码违反它, 然后修复它。 99 | 100 | （注: 迪米特法则：the Law of Demeter, 最少知识原则： the Principle of Least Knowledge） 101 | * Active-Record模式有什么限制和缺陷？ 102 | * Data-Mapper模式和Active-Record模式有什么区别？ 103 | * 空对象模式(Null Object Pattern)的目的是什么？ 104 | * 为什么组合(Composition)比继承(Inheritance)更好？ 105 | * 什么是反腐败层(Anti-corruption Layer)? 106 | * 你可以写一个线程安全的单例(Singleton)类吗？ 107 | * 数据抽象(Data Abstraction)能力是指能改变实现而不影响客户端的这种能力。请构造一个一个例子，违反这个特性，并且尝试修复它。 108 | * 你是如何处理依赖关系地狱(Dependency Hell)的？ 109 | * 为什么说goto语句是恶魔般的存在？ 110 | * 健壮性是进行软件设计时的一个通用原则，它建议 *“发送时要保守，接收时要开放”*。这也经常被写成，“做一个有耐心的读者，做一个谨慎的作者”。你能解释一些这背后的逻辑吗？ 111 | 112 | 译者注： "发送时要保守，接收时要开发"的原文是： "Be conservative in what you send, be liberal in what you accept"，有点类似于“严于律己，宽于待人”的意味。 113 | 114 | #### 代码设计相关问题: [[↑]](#toc) 115 | 116 | * 你在进行软件设计时会考虑软件测试吗？软件测试是如何影响软件设计的？ 117 | * 内聚和耦合的区别是什么？ 118 | * 重构在哪些场景下有用？ 119 | * 代码中的注释有用吗？ 120 | * 设计和架构有什么区别？ 121 | * 为什么在测试驱动开发(TDD)中是先写测试，再写代码？ 122 | * C++支持多继承，Java 允许类实现多个接口。这些特性对正交性有什么影响？使用多继承和使用多接口有区别吗？[这个问题来自Andrew .Hunt 和 David Thomas写的《程序员修炼之道》] 123 | * 在存储过程（Stored Procedures）中写业务逻辑有什么优缺点？ 124 | 125 | #### 语言相关问题: [[↑]](#toc) 126 | 127 | * 告诉我你的首选语言的三个最坏的缺陷。 128 | * 为什么现在函数式编程这么越来越受关注？ 129 | * 闭包是什么？它有什么用途？闭包和类有什么共同点？ 130 | * 泛型有什么用途？ 131 | * 什么是高阶函数？有什么用途？用你的首选语言写个例子出来。 132 | * 讨论一下，如何写一个循环，然后把它转换成递归函数，要避免易变性。 133 | * 有些语言将函数视为第一公民，这是什么意思？ 134 | * 用一个例子说明匿名函数是有用的。 135 | * 什么是动态方法调度(Dynamic Method Dispatch)？ 136 | * 名字空间(Namespace)有什么用？有什么可以替代它的吗？ 137 | * 谈谈Java和C#之间的互操作性(Interoperability) (任选其他两门语言都行) 138 | * 为什么很多软件工程师不喜欢Java？ 139 | * 你认为好的语言好在哪里？差的语言差在哪里？ 140 | * 写两个函数，一个是"引用透明的(Referentially Transparent)"，另一个是"引用不透明的(Referentially Opaque)"。讨论之。 141 | * 什么是栈？什么是堆？ 142 | * 为什么一个语言中，"函数是第一公民"是很重要的？ 143 | * 模式匹配(Pattern Matching)和Switch语句(Switch clauses)的区别在哪儿？ 144 | * 为什么有些语言设计上没有异常机制？这有什么优缺点？ 145 | * 如果`Cat`是一个`Animal`, 那么`TaskCare`是一个`TakeCare`吗？ 146 | 147 | #### web相关问题: [[↑]](#toc) 148 | 149 | * 为什么"第一方cookie(first-party cookie)"和"第三方cookie(third-party cookie)"被如此不同的对待？ 150 | 151 | #### 数据库相关问题: [[↑]](#toc) 152 | 153 | * 如果要你将一个项目从MySQL迁移至PostgreSQL中，你会如何迁移？ 154 | * 为什么```SELECT * FROM table WHERE field = null```不能匹配空的字段？ 155 | * 什么是ACID(原子性，一致性，隔离性，持久性)原则？ 156 | * 你是如何进行数据库模式(Database schema)迁移的？ 157 | * 延迟加载(lazy loading)是如何实现的？什么场景下有用？他有什么缺陷？ 158 | * 什么是N+1问题？ 159 | * 如何找出应用中开销最大的查询？ 160 | 161 | #### 非关系型数据库相关问题: [[↑]](#toc) 162 | 163 | * 什么是最终一致性(Eventual Consistency)？ 164 | * 关于CAP理论，举一些CP、AP、CA系统的例子。 165 | * NoSQL是如何解决可伸缩性的挑战的？ 166 | * 什么情况下你会使用类似于MongoDB的文档数据库而不是关系型数据库（如Mysql或者PostgreSQL）？ 167 | 168 | #### 代码版本管理相关问题: [[↑]](#toc) 169 | 170 | * 为什么在Mercurial或者git中(管理)分支比SVN容易？ 171 | * 分散式版本控制系统（比如git），相比集中式版本控制系统（如svn）有哪些优势和劣势？ 172 | 173 | (注:集中式版本控制系统: Centralized Version Control Systems；分散式版本控制系统: Distributed Version Control Systems) 174 | 175 | * 能描述一下什么是GitHubFlow和GitFlow工作流吗？ 176 | * 什么是rebase？ 177 | * 为什么合并操作(merge)在Mercurial和git中比在SVN和CVS中容易？ 178 | 179 | #### 并发问题: [[↑]](#toc) 180 | 181 | * 为什么我们需要并发呢？解释一下。 182 | * 为什么测试多线程/并发代码这么困难？ 183 | * 什么是竞争条件（Race Condition）？用任何一个语言写一个例子。 184 | * 什么是死锁？用代码解释一下。 185 | * 什么是饿死？ 186 | * 什么是Wait-Free算法？ 187 | 188 | #### 分布式系统相关问题: [[↑]](#toc) 189 | 190 | * 怎么测试一个分布式系统？ 191 | * 什么场景下你会在两个系统中采用异步通信机制？ 192 | * 远程过程调用的通用缺点是什么？ 193 | * 如果你为了可扩展性和鲁棒性而构建一个分布式的系统，分别在封闭安全的网络环境情况下，和地理上的位置不同但是网络环境不是封闭和安全的情况下，你会考虑什么不同的事情？ 194 | * 在Web应用中如何管理容错性？在桌面端呢？ 195 | * 在分布式系统中，如何处理故障？ 196 | * 让我们来谈谈在网络分区(network partitions)情况下的几种（一致性）解决方案吧。 197 | * 你认为分布式计算中有哪些谬论？ 198 | * 你在什么时候会使用Request/Response模式，什么时候使用Publish/Subscribe模式？ 199 | 200 | #### 软件生命周期和团队管理相关问题: [[↑]](#toc) 201 | 202 | * 什么是敏捷（Agility）？ 203 | * 你是如何处理遗留代码（Legacy Code）的？ 204 | * 假设我是你们公司的CEO，请向我解释什么是看板，并且说服我在它上面投资。 205 | * 敏捷（Agility）和瀑布（Waterfall）之间的最大区别是什么？ 206 | * 作为团队管理者，你对会议太多这个问题是如何处理的？ 207 | * 你会如何处理延期很长时间了的项目？ 208 | * "*个体与交互重于过程和工具*"和"*客户协作重于合同谈判*"占了敏捷宣言（Agile Manifesto）的一半，谈论一下这两个观念。 209 | 210 | * 如果你是你们公司的CTO，你会采取什么样的决策？ 211 | * 你觉得项目经理有用吗？ 212 | * 如果要你组织一个弹性工作制的开发团队（即没有强制工作时间的要求），并且假期制度是"按需休假"，你会如何做？ 213 | * 你会如何管理一个人员流动非常高的团队？如何在不加薪的条件下说服团队成员不要离开？ 214 | * 除了代码之外，你最关注你的同事的哪3项素质？ 215 | * 关于代码，你最希望非技术人员能知道的的三件事是什么？ 216 | 217 | #### 逻辑和算法相关问题: [[↑]](#toc) 218 | 219 | * 只用LIFO栈如何构造一个FIFO队列？只用FIFO队列如何构造一个LIFO栈？ 220 | * 写一段有栈溢出的代码。 221 | * 写一个尾递归版本的阶乘函数。 222 | * 使用任何一个语言，写一个REPL，功能是echo你输入的字符串。然后将它演化成一个逆波兰表达式的计算器。 223 | * 如果需要你设计一个文件系统磁盘碎片整理程序，你会如何设计？ 224 | * 写一个生成随机迷宫的程序。 225 | * 写一段有内存泄漏的示例代码。 226 | * 随机生成一个的数字序列，里面每个数字都不同。 227 | * 写一个简单的垃圾回收系统。 228 | * 使用任何一门语言，写一个基本的消息代理。 229 | * 写一个基础的web服务器，然后画一张线路图，展示你将来还想要实现的功能。 230 | * 如何对一个10GB的文件进行排序？如果是10TB的数据，你会采用什么方法？ 231 | * 请实现`rnd()`函数 232 | 233 | #### 软件架构相关问题: [[↑]](#toc) 234 | 235 | * 什么情况下缓存是没用的，甚至是危险的？ 236 | * 为什么事件驱动的架构能提高可扩展性(scalability)？ 237 | * 什么样的代码是可读性强的代码？ 238 | * 紧急设计(Emergent Design)和演化架构(Evolutionary Architecture)之间的区别是什么？ 239 | * 横向扩展(scale out) vs 纵向扩展(scale up): 有什么区别？分别在什么场景下使用？ 240 | * 分布式系统中如何处理"故障切换(failover)"和"用户会话(user session)"？ 241 | * 什么是CQRS(Command Query Responsibility Segregation)?他和最早的Command-Query Separation原则有什么区别？ 242 | * 什么是三层架构？ 243 | * 如何设计一个可扩展性高的系统？ 244 | * 处理C10k问题的策略有哪些？ 245 | * 如果让你来设计一个去中心化的P2P系统，你会如何设计？ 246 | * 为什么CGI的扩展性不好？ 247 | * 在设计系统时，你如何防止供应商依赖([Vendor Lock-in](https://sourcemaking.com/antipatterns/vendor-lock-in))？ 248 | * 在可扩展性上，发布/订阅(Publish-Subscribe)模式有什么缺点？ 249 | * 80年代以后，CPU有哪些变化？这些变化，对编程产生了什么影响？ 250 | * 性能生命周期(performace lifecycle)中，你认为哪个部分是需要考虑进去的？ 如何管理？ 251 | * 除了恶意攻击造成的拒绝服务现象以外，哪些设计或者架构上的问题会导致拒绝服务？ 252 | * 性能和可扩展性之间有什么关系？ 253 | * 什么时候紧耦合是OK的？ 254 | * 一个系统要有什么特征才能适配云计算环境(Cloud Ready)？ 255 | * Does unity of design imply an aristocracy of architects? 256 | 257 | #### 面向服务架构(SOA)和微服务(Microservice)相关问题: [[↑]](#toc) 258 | 259 | * 在SOA中，为什么长期存活的事务(Long-lived transation)不被看好，而Saga却被看好？ 260 | * SOA和MicroService之间有什么区别？ 261 | * 我们来谈谈Web服务的版本管理、版本兼容性、重大变更管理这些事情吧. 262 | * 在saga中事务和补偿操作(compensation operation)之间的区别是什么？在SOA中呢？ 263 | * 微服务不能做得太"微"，你认为什么时候微服务太"微"了？ 264 | * MicroService架构的优劣是什么？ 265 | 266 | #### 安全相关问题: [[↑]](#toc) 267 | 268 | * 什么是双因素认证(Two Factor Authentication)？在一个已有的Web应用中，你如何实现这种机制？ 269 | 270 | #### 比尔盖茨式问题: [[↑]](#toc) 271 | 272 | * 如果你把一面镜子放在扫描仪上，会发生什么？ 273 | * 假设有一个和你完全一样的克隆人，而他是你的上司，你愿意和他工作吗？ 274 | * 现在请你面试一下我。 275 | * 为什么Quora上的回答会比Yahoo Answer上的回答好？ 276 | * 对手是现代语言，你的任务是要为Cobol辩护，你会如何进行？ 277 | * 10年后的你是什么样子？ 278 | * 假设你是我老板，我被解雇了。你会如何通知我？ 279 | * 我想要重构一个系统，而你想要从头重写。我们来争论一下该怎么弄吧。然后我们反转角色，再争论一下。 280 | * 老板要你对公司撒谎，你的反应是什么？ 281 | * 如果你可以穿越到以前，你会给年轻时候的你什么建议？ 282 | 283 | #### 代码示例问题: [[↑]](#toc) 284 | 285 | * 这段Javascript函数的输出是什么？ 286 | 287 | ```javascript 288 | function hookupevents() { 289 | for (var i = 0; i < 3; i++) { 290 | document.getElementById("button" + i) 291 | .addEventListener("click", function() { 292 | alert(i); 293 | }); 294 | } 295 | } 296 | ``` 297 | 298 | * 关于类型擦除(Type Erasure)，这段Java代码的输出是什么？为什么？ 299 | 300 | ```java 301 | ArrayList li = new ArrayList(); 302 | ArrayList lf = new ArrayList(); 303 | if (li.getClass() == lf.getClass()) // evaluates to true 304 | System.out.println("Equal"); 305 | ``` 306 | 307 | * 你能指出哪儿有内存泄漏吗？ 308 | 309 | ```java 310 | public class Stack { 311 | private Object[] elements; 312 | private int size = 0; 313 | private static final int DEFAULT_INITIAL_CAPACITY = 16; 314 | 315 | public Stack() { 316 | elements = new Object[DEFAULT_INITIAL_CAPACITY]; 317 | } 318 | 319 | public void push(Object e) { 320 | ensureCapacity(); 321 | elements[size++] = e; 322 | } 323 | 324 | public Object pop() { 325 | if (size == 0) 326 | throw new EmptyStackException(); 327 | return elements[--size]; 328 | } 329 | 330 | /** 331 | * Ensure space for at least one more element, roughly 332 | * doubling the capacity each time the array needs to grow. 333 | */ 334 | private void ensureCapacity() { 335 | if (elements.length == size) 336 | elements = Arrays.copyOf(elements, 2 * size + 1); 337 | } 338 | } 339 | ``` 340 | 341 | * `if`语句，或者更加通用点，条件表达式通常是过程式编程/命令式编程的形式。你能去掉这段代码中的`switch`语句，用面向对象的方式来修改这段代码吗？ 342 | 343 | ```java 344 | public class Formatter { 345 | 346 | private Service service; 347 | 348 | public Formatter(Service service) { 349 | this.service = service; 350 | } 351 | 352 | public String doTheJob(String theInput) { 353 | String response = service.askForPermission(); 354 | switch (response) { 355 | case "FAIL": 356 | return "error"; 357 | case "OK": 358 | return String.format("%s%s", theInput, theInput); 359 | default: 360 | return null; 361 | } 362 | } 363 | } 364 | ``` 365 | 366 | * 你能去掉这里的`if`语句，将它改成更加面向对象吗？ 367 | 368 | ```java 369 | public class TheService { 370 | private final FileHandler fileHandler; 371 | private final FooRepository fooRepository; 372 | 373 | public TheService(FileHandler fileHandler, FooRepository fooRepository) { 374 | this.fileHandler = fileHandler; 375 | this.fooRepository = fooRepository; 376 | } 377 | 378 | public String Execute(final String file) { 379 | 380 | final String rewrittenUrl = fileHandler.getXmlFileFromFileName(file); 381 | final String executionId = fileHandler.getExecutionIdFromFileName(file); 382 | 383 | if ((executionId == "") || (rewrittenUrl == "")) { 384 | return ""; 385 | } 386 | 387 | Foo knownFoo = fooRepository.getFooByXmlFileName(rewrittenUrl); 388 | 389 | if (knownFoo == null) { 390 | return ""; 391 | } 392 | 393 | return knownFoo.DoThat(file); 394 | } 395 | } 396 | ``` 397 | 398 | * 如何重构这段代码？ 399 | 400 | ```javascript 401 | function() 402 | { 403 | HRESULT error = S_OK; 404 | 405 | if(SUCCEEDED(Operation1())) 406 | { 407 | if(SUCCEEDED(Operation2())) 408 | { 409 | if(SUCCEEDED(Operation3())) 410 | { 411 | if(SUCCEEDED(Operation4())) 412 | { 413 | } 414 | else 415 | { 416 | error = OPERATION4FAILED; 417 | } 418 | } 419 | else 420 | { 421 | error = OPERATION3FAILED; 422 | } 423 | } 424 | else 425 | { 426 | error = OPERATION2FAILED; 427 | } 428 | } 429 | else 430 | { 431 | error = OPERATION1FAILED; 432 | } 433 | 434 | return error; 435 | } 436 | ``` 437 | 438 | --------------------------------------------------------------------------------