C++11中delete和default的用法详解

class DataOnly {
private:
    int  data_;
};   

class DataOnly {
public:
    DataOnly ()                  // default constructor
    ~DataOnly ()                 // destructor
    DataOnly (const DataOnly & rhs)         　 　  // copy constructor
    DataOnly & operator=(const DataOnly & rhs)    // copy assignment operator
    DataOnly (const DataOnly && rhs)         // C++11, move constructor
    DataOnly & operator=(DataOnly && rhs)    // C++11, move assignment operator
};　　　   

class LeafOfTree{ 
  // ... 
};　　　　 

LeafOfTree  leaf1;
LeafOfTree  leaf2;
LeafOfTree  leaf3(leaf1);     // attempt to copy Leaf1 — should not compile!
Leaf1 = Leaf2;               // attempt to copy Leaf2 — should not compile!　

class LeafOfTree{
private:
    LeafOfTree( const LeafOfTree& );    　　　　　　 // not defined
    LeafOfTree & operator=( const LeafOfTree& );    // not defined
};　　  

// A macro to disallow the copy constructor and operator= functions 
// This should be used in the priavte:declarations for a class
   #define    DISALLOW_COPY_AND_ASSIGN(TypeName) \
   TypeName(const TypeName&);                \
   TypeName& operator=(const TypeName&)　　

class LeafOfTree{
public:
　　LeafOfTree() = default;
　　~LeafOfTree() = default;
　　LeafOfTree(const LeafOfTree&) = delete;　　// mark copy ctor or copy assignment operator as deleted functions
　　LeafOfTree & operator=(const LeafOfTree&) = delete; 
};　 

bool IsLucky(int number);        // original function
bool IsLucky(char) = delete;     // reject chars
bool IsLucky(bool) = delete;     // reject bools
bool IsLucky(double) = delete;   // reject doubles and floats　　 

if (IsLucky('a')) …     // error !    call to deleted function
if (IsLucky(true)) …    // error !
if (IsLucky(3.5)) …     // error !　　 

class Widget {
public:
    template<typename T>
    void ProcessPointer(T* ptr) { … }
private:
    template<>             
    void ProcessPointer<void>(void*);    // error!
};　　

class Widget {
public:
    template<typename T>
    void ProcessPointer(T* ptr) { … }
};
template<> 
void Widget::ProcessPointer<void>(void*) = delete; // still public, but deleted