C++核心準則C102-109:容器的基本要求

火歐珀

C.102: Give a container move operations

C.102:為容器實現(xiàn)移動操作?

Reason（原因）

Containers tend to get large; without a move constructor and a copy constructor an object can be expensive to move around, thus tempting people to pass pointers to it around and getting into resource management problems.

容器會變得越來越大；如果對象沒有移動構造函數(shù)和拷貝構造函數(shù)，移動它的成本就會很高，其結果就是導致人們更愿意傳遞指向?qū)ο蟮闹羔槒亩鹳Y源管理方面的問題。

Example(示例)

Sorted_vector?read_sorted(istream&?is)
{
????vector?v;
????cin?>>?v;???//?assume?we?have?a?read?operation?for?vectors
????Sorted_vector?sv?=?v;??//?sorts
????return?sv;
}

A user can reasonably assume that returning a standard-like container is cheap.

用戶可以合理地假設返回和標準庫類似的容器是低成本的。

Enforcement(實施建議)

???

C.103: Give a container an initializer list constructor

C.103:為容器實現(xiàn)一個初始化類別形式的構造函數(shù)?

Reason(原因)

People expect to be able to initialize a container with a set of values. Familiarity.

人們希望可以通過一組值來初始化容易。這是友好性方面的考慮。

Example(示例)

Sorted_vector?sv?{1,?3,?-1,?7,?0,?0};?
//?Sorted_vector?sorts?elements?as?needed

Enforcement(實施建議)

???

C.104: Give a container a default constructor that sets it to empty

C.104:為容器實現(xiàn)一個將容器初始化為空的默認構造函數(shù)?

Reason(原因)

To make it?Regular.

保持容器的常規(guī)性。

Example(示例)

vector>?vs(100);????//?100?Sorted_sequences?each?with?the?value?""

Enforcement(實施建議)

???

C.109: If a resource handle has pointer semantics, provide?*?and?->

C.109:如果資源句柄包含指針語義，提供*和->運算符

Reason(原因)

That's what is expected from pointers. Familiarity.

這是來自指針類型的期望。友好型方面的考慮。

Example(示例)

???

Enforcement(實施建議)

???

原文鏈接

https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#c102-give-a-container-move-operations

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