Effective C++ 改善程序与设计的55个具体做法 读书笔记



Effective C++ 改善程序与设计的55个具体做法 读书笔记
1.让自己习惯C++
  Accustoming Yourself to C++
条款01：视C++为一个语言联邦
        View C++ as a federation of languages
        1、主要分为4部分：C、Object-Oriented C++、Template C++、STL
条款02：尽量以const,enum,inline替换#define
        Prefer consts,enums and inlines to #define
        1、对于单纯常量，最好以const对象或enums替换#define。
        2、对于形似函数的宏（macros），最好改用inline函数替换#defines。
条款03：尽可能使用const
        Use const whenever possible
        真实程序中const对象大多用于passed by pointer-to-const或
        passed by reference-to-const的传递结果。
        1、将某些东西声明为const可帮助编译器侦测出错误用法。
           const可被施加于任何作用域内的对象、函数参数、函数返回类型、成员函数本体。
        2、编译器强制实施bitwise constness，但你编写程序时应该使用“概念上的常量性”（conceptual constness）。
        3、当const和non-const成员函数有着实质等价的实现时，令non-const版本调用const版本可避免代码重复。
条款04：确定对象被使用前已先被初始化
        Make sure that objects are initialized before they're used
        C++规定，对象的成员变量的初始化动作发生在进入构造函数本体之前。
        1、为内置型对象进行手工初始化，因为C++不保证初始化它们。
        2、构造函数最好使用成员初值列（member initialization list），
           而不要在构造函数本体内使用赋值操作（assignment）。
           初值列列出的成员变量，其排列次序应该和他们在class中的声明次序相同。
        3、为免除“跨编译单元之初始化次序”问题，请以local static对象替换non-local static对象。

2.构造/析构/赋值运算
  Constructors,Destructors and Assignment Operators
条款05：了解C++默默编写并调用哪些函数
        Know what functions C++ silently writes and calls
条款06：若不想使用编译器自动生成的函数，就该明确拒绝
        Explicitly disallow the use of compiler-generated functions you do not want
条款07：为多态基类声明virtual析构函数
        Declare destructors virtual in polymorphic base classes
条款08：别让异常逃离析构函数
        Prevent exceptions from leaving destructors
条款09：绝不在构造和析构过程中调用virtual函数
        Never call virtual functions during construction or destruction
条款10：令operator=返回一个refernce to *this
        Have assignment operators return a reference to *this
条款11：在operator=中处理“自我赋值”
        Handle assignment to self in operator=
条款12：复制对象时勿妄其每一个成分
        Copy all parts of an object

3.资源管理
  Resource Management
条款13：以对象管理资源
        Use objects to manage resources
条款14：在资源管理类中小心copying行为
        Think carefully about copying behavior in resource-managing classes
条款15：在资源管理类中提供对原始资源的访问
        Provide access to raw resources in resource-managing classes
条款16：成对使用new和delete时要采取相同形式
        Use the same form in corresponding uses of new and delete
条款17：以独立语句将newed对象置入智能指针
        Store newed objects in smart pointers in standalone statements

4.设计与声明
  Designs and Declarations
条款18：让接口容易被正确使用，不易被误用
        Make interfaces easy to use correctly and hard to use incorrectly
条款19：设计class犹如设计type
        Treat class design as type design
条款20：宁以pass-by-reference-to-const替换pass-by-value
        Prefer pass-by-reference-to-const to pass-by-value
条款21：必须返回对象时，别妄想返回其reference
        Don't try to return a reference when you must return an object
条款22：将成员变量声明为private
        Declare data members private
条款23：宁以non-member、non-friend替换member函数
        Prefer non-member non-friend functions to member functions
条款24：若所有参数皆需类型转换，请为此采用non-member函数
        Declare non-member functions when type conversions should apply to all parameters
条款25：考虑写出一个不抛异常的swap函数
        Consider support for a non-throwing swap

5.实现
  Implementations
条款26：尽可能延后变量定义式的出现时间
        Postpone variable definitions as long as possible
条款27：尽量少做转型动作
        Minimize casting
条款28：避免返回handles指向对象内部成分
        Avoid returning "handles" to object internals
条款29：为“异常安全”而努力是值得的
        Strive for exception-safe code
条款30：透切了解inlining的里里外外
        Understand the ins and outs of inlining
条款31：将文件间的编译依存关系降至最低
        Minimize compilation dependencies between files

6.继承与面向对象设计
  Inheritance and Object-Oriented Design
条款32：确定你的public继承塑模出is-a关系
        Make sure public inheritance models "is-a"
条款33：避免遮掩继承而来的名称
        Avoid hiding inherited names
条款34：区分接口继承和实现继承
        Differentiate between inheritance of interface and inheritance of implementation
条款35：考虑virtual函数以外的其他选择
        Consider alternatives to virtual functions
条款36：绝不重新定义继承而来的non-virtual函数
        Never redefine an inherited non-virtual function
条款37：绝不重新定义继承而来的缺省参数值
        Never redefine a function's inherited default parameter value
条款38：通过复合塑模出has-a或“根据某物实现出”
        Model "has-a" or "is-implemented-in-terms-of" through composition
条款39：明智而审慎地使用private继承
        Use private inheritance judiciously
条款40：明智而审慎地使用多重继承
        Use multiple inheritance judiciously

7.模板与泛型编程
  Templates and Generic Programming
条款41：了解隐式接口和编译期多态
        Understand implicit interfaces and compile-time polymorphism
条款42：了解typename的双重意义
        Understand the two meaning of typename
条款43：学习处理模板化基类内的名称
        Know how to access names in templatized base classes
条款44：将与参数无关的代码抽离templates
        Factor parameter-independent code out of templates
条款45：运用成员函数模板接受所有兼容类型
        Use member function templates to accept "all compatible types"
条款46：需要类型转换时请为模板定义非成员函数
        Define non-member functions inside templates when type conversions are desired
条款47：请使用traits classes表现类型信息
        Use traits classes for information about types
条款48：认识template元编程
        Be aware of template metaprogramming

8.定制new和delete
  Customizing new and delete
条款49：了解new-handler的行为
        Understand the behavior of the new-handler
条款50：了解new和delete的合理替换时机
        Understand when it makes sense to replace new and delete
条款51：编写new和delete时需固守常规
        Adhere to convention when writing new and delete
条款52：写了placement new也要写placement delete
        Write placement delete if you write placement new

9.杂项讨论
  Miscellany
条款53：不要轻忽编译器的警告
        Pay attention to compiler warnings
条款54：让自己熟悉包括TR1在内的标准程序库
        Familiarize yourself with the standard library, including TR1
条款55：让自己熟悉Boost
        Familiarize yourself with Boost