Effective Modern C++ 9.4分
读书笔记 第2页
Cynosure

Things to Remember

Item 8

• Prefer nullptr to 0 and NULL.

• Avoid overloading on integral and pointer types.

Item 9: Prefer alias declarations to typedef s

• typedefs don’t support templatization, but alias declarations do.

• Alias templates avoid the “::type” suffix and, in templates, the “typename” prefix often required to refer to typedefs.

• C++14 offers alias templates for all the C++11 type traits transformations.

Item 10: Prefer scoped enum s to unscoped enum s.

• C++98-style enums are now known as unscoped enums.

• Enumerators of scoped enums are visible only within the enum. They convert to other types only with a cast.

• Both scoped and unscoped enums support specification of the underlying type. The default underlying type for scoped enums is int. Unscoped enums have no default underlying type.

• Scoped enums may always be forward-declared. Unscoped enums may be forward-declared only if their declaration specifies an underlying type.

Item 11: Prefer deleted functions to private undefined ones.

• Prefer deleted functions to private undefined ones.

• Any function may be deleted, including non-member functions and template instantiations.

Item 12: Declare overriding functions override.

• Declare overriding functions override.

• Member function reference qualifiers make it possible to treat lvalue and

rvalue objects (*this) differently

Item 13: Prefer const_iterators to iterators.

• Prefer const_iterators to iterators.

• In maximally generic code, prefer non-member versions of begin, end,

rbegin, etc., over their member function counterparts.

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Item 14:

• noexcept is part of a function’s interface, and that means that callers may depend on it.

• noexcept functions are more optimizable than non-noexcept functions.

• noexcept is particularly valuable for the move operations, swap, memory deallocation functions, and destructors.

• Most functions are exception-neutral rather than noexcept.

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Item 15 constexpr

• constexpr objects are const and are initialized with values known during compilation.

• constexpr functions can produce compile-time results when called with arguments whose values are known during compilation.

• constexpr objects and functions may be used in a wider range of contexts than non-constexpr objects and functions.

• constexpr is part of an object’s or function’s interface.

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