引用代替getter？ [英] Reference in place of getters?

问题描述

<$> p $ p> class X
{
int mP;
public：
const int& P;
X（）：P（mP）{}
};


及更高版本

 code> X xl; 
 int h = xl.P; 
  

解决方案

这些都不好：

  class X {public：int x; }; 
 class X {
 private：int m_x; 
 public：const int& get（）const {return m_x; } 
 public：void set（const int& other）{m_x = other; } 
}; 
 class X {
 private：int m_x; 
 public：const int& x（）const {return m_x; } 
 public：void x（const int& other）{m_x = other; } 
}; 
 class X {
 private：int m_x; 
 public：const int& x（）const {return m_x; } 
 public：int& x（）{return m_x; } 
}; 
  

选择一个，这是一个设计决定。

Having'const int& x'发布私有成员将工作：

  class X {
 private：int m_x; 
 public：const int& X; 
 public：X（）：m_x（0），x（m_x）{} 
 //注意复制和赋值
}; 
  

成本是更大的内存占用。

in C++ is it a bad practice to use reference in place of getters?

for example:

class X
{
    int mP;
 public:
    const int& P;
    X():P(mP){}
}; 

and later

X xl;
int h = xl.P;

解决方案

None of this is good:

class X { public: int x; };
class X {
    private: int m_x;
    public: const int& get() const { return m_x; }
    public: void set(const int& other)  { m_x = other; } 
};
class X {
    private: int m_x;
    public: const int& x() const { return m_x; }
    public: void x(const int& other)  { m_x = other; } 
};
class X {
    private: int m_x;
    public: const int& x() const { return m_x; }
    public: int& x()  { return m_x; }
};

Pick one, it's a design decision.

Having 'const int& x' to publish the private member will work:

class X {
    private: int m_x;
    public: const int& x;
    public: X() : m_x(0), x(m_x) {}
    // Take care for copy and assignment
};

The cost is a larger memory footprint.

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