Negative tive C ++ (10) returns a reference to this object (retrun * this) when the value assignment operator is overloaded)

Problem focus:

This rule is short, but it is often the place where such details can improve the quality of your code. The Details determine the success or failure. Let's learn the rules that need to be followed when this overload assignment operator is used.

Start with an example: Demo

// Chained value assignment x = y = z = 15; // The above expression is equivalent to x = (y = (z = 15 ));

In order to realize the above chained assignment, the value assignment operator must return a reference pointing to the real parameter on the left of the operator. That is:

Class Widget {public: Widget & operator = (const Widget & rhs) {... return * this ;}};

This can be considered as a Protocol applicable to all assignment-related operations.

Class Widget {public :... widget & operator + = (const Widget & rhs ){.... return * this;} Widget & operator = (const Widget & rhs ){... return * this ;}};

Reasons for using this Protocol: All built-in types and types provided by the standard library, such as string, vector, complex, tr1: shared_ptr, or the type to be provided, are shared. Unless you have a good reason to be unconventional, you should follow suit ..
Conclusion: The overload assignment operator returns a reference to * this of the current object)

References: Objective C ++ 3rd