C++,operator=

Why is operator= worth noticing?

Syntactically speaking, the following program can be compiled and passed, and I use it in another note example.

classa1{ Public:    int operator=(intA//The argument is int, the syntax is passed but the logic does not pass.     {        return 8; }    int operator+(inta) {return 9; }    int operator= (A1 &a)//return int, meaningless or illogical,{cout<<"operator= (A1 &a)"<<Endl; return 0; }};
Http://www.cnblogs.com/mylinux/p/4094808.html

In fact, like the copy constructor, we need to consider more questions:

1. Shallow copy of the problem. [1]//Constructor, Operator= is the same as the constructor.

Precautions: [2]//effective_c++

2. Why opreator= to return to *this?
In order to support chain calls such as A=b=c
3. Why not return to const Goodobject&?
For operations that are compatible with compilers (A=B) =c
4. Why pass in const goodobject& RHS
The following operations are primarily supported:
Goodobject A;
Const Goodobject B;
A = b;
5. Why should there be a judgment like if (this! = &RHS)
The main thing is to avoid self-assignment a=a such a situation occurs.
6. Don't forget to rewrite the copy constructor

7. Example: [3]

Examples of reference users:

classsampleclass{Private:         intA; Doubleb; float*p; Public: SampleClass&operator= (Constsampleclass&s) {if( This= = &s)return* This;//a sentence to solve a self-assigned valueA =S.A.; b=s.b;                   Delete p; P=New float(*S.P); return* This; }};

This is written in the book://Although there is a TMP, but the recommended reference

sampleclass&operator= (Constsampleclass&s) {         if( This= = &s)return* This;//A =S.A.; b=s.b; float* tmp = p;//The old pointers are saved firstp =New float(*S.P);//then apply for new space, if the application fails, p still points to the original address spaceDelete tmp;//can walk here, indicating that the application space is successful, then you can delete the old content         return* This;}

Reference:

A brief analysis of 1.c++ depth copy
Http://www.jizhuomi.com/software/291.html

The 2.operator= function.

http://blog.csdn.net/howlet2/article/details/5090756

3. Reading notes _EFFECTIVE_C++_ clause 11: Handling Self-assignment in operator=
Http://www.cnblogs.com/jerry19880126/archive/2013/03/21/2972648.html

C++,operator=