C++ overload assignment operator and 11 choose 5 platform repair

1. What should be returned by the overloaded assignment function in C++?

11 choose 5 platform repair (enterprise E: 1793 408) class overload assignment operators generally exist as member functions, so what type should the function return? Refer to the assignment operation of the built-in type, such as

Int x,y,z

X=y=z=15

The assignment behavior is equivalent to x = (y = (zip15)), that is, the assignment operation should return a reference to the left Operand. Therefore, in order to be compatible with the built-in type, the overloaded assignment operator in the class should return a reference to the left Operand, namely * this, as shown in the declaration of the overloaded assignment operation function of class A

Class A {}

A & A / A / A

2. Ensure that the overload assignment operation has good behavior

For assignment operations, the first thing you should think about is how to handle self-assignment, especially when the class contains pointer-type data, as follows

Class MyString {

Public:

...

MyString (char * p=NULL)

MyString& operator= (const MyString&)

Private:

Char * str

}

MyString a ("hello")

MyString b ("world")

Abaca

We know that when assigning a value, we first release the resources of the left Operand, and then assign the left Operand according to the right Operand. The assignment function is as follows