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Use private copy constructor and assignment operator to avoid object copying

Use private copy constructor and assignment operator to avoid object copying

If you don’t want users of your class to be able to assign objects of its type (password string objects are a good example), you can declare a private assignment operator and copy constructor. Please note that the compiler-synthesized copy constructor and assignment operator are public, therefore, you have to define them explicitly as private members in this case. For example:

 class NoCopy {private:NoCopy&  operator = (const NoCopy& other) { /*..*/}NoCopy(const NoCopy& other) {/*..*/}public://...};void f(){NoCopy nc; //fine, default constructor calledNoCopy nc2(nc); //compile time error; attempt to call a private copy constructornc2 = nc; //also a compile time error; operator= is private}

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