Point of Offer: assignment operator function

There are a few things to consider when defining an assignment operator function:

(1) The return type of the function must be a reference, because only a reference can be returned for continuous assignment

(2) The passed parameter declaration is a constant reference, which can improve the efficiency of the Code, while the assignment function does not change the incoming instance state

(3) Be sure to remember to release the memory of the instance itself, or the program is prone to memory leaks

(4) Note that the incoming parameter and the current instance is not the same instance, if it is the same, you do not have to do the assignment, directly return.

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Point of Offer: assignment operator function