進階軟體工程師面試問題 Interview SeniorSoftwareEngineers

hanselman這篇文章很有意思，儘管不是每個問題都很值得作為面試問題出現，但是很多都值得去仔細想想。

一個優秀的面試問題，尤其是針對Senior Engineer的面試問題，不應該僅僅是問某個api的用法，某個很容易從協助中找到的內容。有發散性，可以基於問題進行擴充的問題才是一個比較好的問題。

下面是一個非常長的問題列表，主要是關於物件導向設計，設計模式，以及一些實際工程中會用到概念，都是比較基本的，但是也非常能考察一個進階工程師的水平，因為會牽涉到非常多方面。

另外要說明的是下面很多概念性問題可以直接從wiki維基百科上找到答案。另外我會標記出個人覺得比較值得問的問題。

原文在這裡 http://www.hanselman.com/blog/NewInterviewQuestionsForSeniorSoftwareEngineers.aspx

# What is something substantive that you’ve done to improve as a developer in your career?

有沒有做過什麼比較實質性的事情來提升你的程式員職業水平？

好問題。我的回答：這個很難說，我的做法是堅持學習，堅持寫技術類部落格。另外有些經驗在這裡提到過http://sunxiunan.com/?p=1799

# Would you call yourself a craftsman (craftsperson) and what does that word mean to you?

不敢叫自己大師啊，那得多牛逼？！

# Implement a <basic data structure> using <some language> on <paper|whiteboard|notepad>.

用某種語言在紙面上實現一個基本的資料結構。(用近似真實格式的虛擬碼來表達?)

好問題。我的回答，找一本基礎的資料結構書籍吧，比如這一本《資料結構與演算法分析：C語言描述（原書第2版）》

# What is SOLID?

參考http://en.wikipedia.org/wiki/Solid_%28object-oriented_design%29

這個solid不是說“結實的”，而是物件導向五大原則的簡稱：單一責任原則，開閉原則，萊西科夫替換原則，介面分離原則，依賴倒置原則。

好問題。這幾個原則的確應該背下來，太基礎了。

# Why is the Single Responsibility Principle important?

為什麼單一責任原則重要？

好問題。我的回答，因為職責明確，設計就不容易混亂，即使有後續變化也是可控的。

# What is Inversion of Control? How does that relate to dependency injection?

參考http://en.wikipedia.org/wiki/Inversion_of_control

實際中的例子，通知開會，一種可以打電話通知到每個人（這屬於中心控制型的，必須有個controller/manager之類的）；也可張貼一個告示，大家自己來看，這屬於事件響應型的。

# How does a 3 tier application differ from a 2 tier one?

三層應用與兩層應用的區別是什嗎？

我只知道MVC三層應用。

# Why are interfaces important?

為什麼介面重要？

好問題。介面的重要在於消費者（用戶端）不需要瞭解生產者（服務端）的細節，介面相當於合約，當合約不變的時候，誰生產如何生產都不是消費者關心的問題。

# What is the Repository pattern? The Factory Pattern? Why are patterns important?

關於設計模式的問題，

第一個參考http://msdn.microsoft.com/en-us/library/ff649690.aspx

原廠模式基本上是眾人皆知的模式了。

為何模式重要？我不覺得模式重要，模式的重要性在於讓你能“喔！原來是這個”。但是對於一個沒有幾年編程經驗的開發人員而言，模式只能讓你更混亂。

設計模式很多情況下是通過加入一個抽象層來解決耦合之類的問題，但是層次越多越複雜，就好比單位中領導的層級越多越官僚一樣。

# What are some examples of anti-patterns?

反模式？少用模式，多寫點清晰的代碼吧。

# Who are the Gang of Four? Why should you care?

四人組，名字叫不上來，但是他們是設計模式的總結者。

# How do the MVP, MVC, and MVVM patterns relate? When are they appropriate?

這也是微軟特色，大家只要知道MVC就行了，其實大家現在用的都是MVC，但是由於水平高低，效果就是千差萬別。

啥MVP，MVVM我不知啊（也不是不知，只知道MVVM是wpf的一個概念，可我也不用wpf啊）

# Explain the concept of Separation of Concerns and it’s pros and cons.

參考http://en.wikipedia.org/wiki/Separation_of_concerns

我也不是瞭解的很細。

# Name three primary attributes of object-oriented design. Describe what they mean and why they’re important.

封裝/繼承/多態？

參考這裡吧http://en.wikipedia.org/wiki/Object-oriented_programming

學C++這幾個概念是基礎啊

# Describe a pattern that is NOT the Factory Pattern? How is it used and when?

不是原廠模式，我知道個單件模式。還有模板模式/facade模式/strategy模式，具體也要翻翻書，很少有意識的套用。

# You have just been put in charge of a legacy code project
with maintainability problems. What kind of things would you look to
improve to get the project on a stable footing?

第一步，先把代碼用最大警告層級編譯一遍，然後fix所有值得fix的warning。

好問題。

# Show me a portfolio of all the applications you worked on, and tell me how you contributed to design them.

如果光是看文檔，很難說到實質上。

好問題。

# What are some alternate ways to store data other than a
relational database? Why would you do that, and what are the trade-offs?

好問題，很多啦，記憶體/檔案/雲端儲存/nosql等等。tradeoff就看你的應用需求了。blabla。。。

# Explain the concept of convention over configuration, and
talk about an example of convention over configuration you have seen in
the wild.

好問題。

我能想到的就是買車開車，很少有人買到車以後，拿著說明書調試這個那個，一般都是直接上路，因為汽車廠會給你一個比較不錯的預設配置，也就是所謂的“方便”。

這個方便也保證了你開其它車，基本上都差不多，不用重新設定或者學習什麼。

所謂方便”convention“就是把相對不錯/比較普遍適用的配置都內建好了，用就是了。

# Explain the differences between stateless and stateful systems, and impacts of state on parallelism.

解釋有狀態與無狀態系統，以及有狀態系統在並行上的影響。

好問題。這個說不好。有狀態系統因為保持狀態，並行執行階段的訪問/修改需要有鎖同步機制。

# Discuss the differences between Mocks and Stubs/Fakes and where you
might use them (answers aren’t that important here, just the discussion
that would ensue).

跟TDD相關的問題。不會哦。

# Discuss the concept of YAGNI and explain something you did recently that adhered to this practice.

解釋“YAGNI”。

最簡單的例子是當我們定義介面，會特意預留出一兩個參數，說是為了將來使用，其實，沒有將來。屁嘞！你根本不需要它！

不是說不考慮可擴充性，但是要基於可預測的基礎上。

# Explain what is meant by a sandbox, why you would use one, and identify examples of sandboxes in the wild.

比如把虛擬機器比如vmware virtualbox作為沙箱，用起來可以隔離風險。大不了重啟，或者刪除之。

# Concurrency

* What’s the difference between Locking and Lockless (Optimistic and Pessimistic) concurrency models?

* What kinds of problems can you hit with locking model? And a lockless model?

* What trade offs do you have for resource contention?

* How might a task-based model differ from a threaded model?

* What’s the difference between asynchrony and concurrency?

這些問題不錯。並發相關的問題，設計多使用者高效能系統必知。

# Are you still writing code? Do you love it?

我喜歡編程。

# You’ve just been assigned to a project in a new technology how would you get started?

如果是我，先瞭解這個技術的風險。小心求證，盡量縮小使用範圍，否則是很致命的。

# How does the addition of Service Orientation change systems? When is it appropriate to use?

不懂。

# What do you do to stay abreast of the latest technologies and tools?

我跟的很緊哦！

# What is the difference between "set" logic, and "procedural" logic. When would you use each one and why?

不懂要問什麼。

# What Source Control systems have you worked with?

ClearCase.很難用。最近不少問題都是跟CC相關的。

# What is Continuous Integration? Have you used it and why is it important?

持續整合。這個概念跟TDD也掛鈎。

# Describe a software development life cycle that you’ve managed.

涉及的還是傳統模型，不是scrum型的。

# How do you react to people criticizing your code/documents?

批評沒問題，但是要有道理有根據。

# Whose blogs or podcasts do you follow? Do you blog or podcast?

這就很多了，看我以前寫的文章吧。

# Tell me about some of your hobby projects that you’ve written in your off time.

主要是Lua和Py的，appengine上的比較多。

# What is the last programming book you read?

最近看得是《C++ FAQs》中文版。翻譯的一般，內容也比較陳舊。更堅定了我使用C風格的C++的決心。

# Describe, in as much detail as you think is relevant, as
deeply as you can, what happens when I type "cnn.com" into a browser and
press "Go".

儘可能詳細深入的描述，當你在瀏覽器敲網址然後go後面的技術細節。

好問題。很發散，絕對能看出面試者的技術厚度。

# Describe the structure and contents of a design document, or a set of design documents, for a multi-tiered web application.

# What’s so great about <cool web technology of the day>?

# How can you stop your DBA from making off with a list of your users’ passwords?

# What do you do when you get stuck with a problem you can’t solve?

參考這裡電腦編程新人入行指導 

http://sunxiunan.com/?p=961

# If your database was under a lot of strain, what are the first few things you might consider to speed it up?

先profiling哦！

# What is SQL injection?

# What’s the difference between unit test and integration test?

單元測試應該是程式員做。整合測試就牽扯到tester了。

# Tell me about 3 times you failed.

# What is Refactoring ? Have you used it and it is important? Name three common refactorings.

我一直在重構自己的代碼。重構原則參考這裡

C++項目代碼規範（偶自用）http://sunxiunan.com/?p=1787

# You have two computers, and you want to get data from one to the other. How could you do it?

具名管道，socket，共用資料夾，路子還是很多的。

# Left to your own devices, what would you create?

# Given Time, Cost, Client satisfaction and Best Practices,
how will you prioritize them for a project you are working on? Explain
why.

這個很值得問。

# What’s the difference between a web server, web farm and web garden? How would your web application need to change for each?

# What value do daily builds, automated testing, and peer reviews add to a project? What disadvantages are there?

都是為了提升代碼品質，但是會延長工期。

# What elements of OO design are most prone to abuse? How would you mitigate that?

# When do you know your code is ready for production?

看bug fix的統計曲線。