C.131: Avoid trivial getters and setters
C.131: 避免無意義的getters和setters
Reason(原因)
A trivial getter or setter adds no semantic value; the data item could just as well be public.
無意義的getter和setter不會增加任何語義上的價值，數據項只要定義為public就好。
Example(示例)
<code>class Point { // Bad: verbose int x; int y;public: Point(int xx, int yy) : x{xx}, y{yy} { } int get_x() const { return x; } void set_x(int xx) { x = xx; } int get_y() const { return y; } void set_y(int yy) { y = yy; } // no behavioral member functions};/<code>Consider making such a class a struct -- that is, a behaviorless bunch of variables, all public data and no member functions.
考慮將這樣的類定義為struct--也就是說，不包含行為的數據群，所有數據都公開，沒有成員函數。
<code>struct Point { int x {0}; int y {0};};/<code>Note that we can put default initializers on member variables: C.49: Prefer initialization to assignment in constructors.
注意我們可以為成員變量設置初始化器：C.49:初始化比在構造函數中複製更好。
Note(注意)
The key to this rule is whether the semantics of the getter/setter are trivial. While it is not a complete definition of "trivial", consider whether there would be any difference beyond syntax if the getter/setter was a public data member instead. Examples of non-trivial semantics would be: maintaining a class invariant or converting between an internal type and an interface type.
這條準則的關鍵是getter/setter的語義是不是有意義。如果不能完全定義“無意義”，考慮如果getter/setter如果是公有成員的話是否存在任何的不同。有意義的語義的示例：維持類的不變量或者在內部數據類型和接口數據類型之間進行轉換。
Enforcement(實施建議)
Flag multiple get and set member functions that simply access a member without additional semantics.
如果存在多個get和set成員函數只是簡單地訪問數據成員卻不包含附加意義，進行提示。
原文鏈接：
https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#c130-for-making-deep-copies-of-polymorphic-classes-prefer-a-virtual-clone-function-instead-of-copy-constructionassignment
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