CPP operator overloading
[CPP Overloading](https://texonom.com/cpp-overloading-87476e40ab924e6b8642db70b70ddc29) 


+, - 정의 등
<<
comma
4 + - / *


```typeconst Class operator + (const Class& var1, const Class& var2){}```
parameter is const because it should not be changed
return type is const because it is anonymous object. It is not good so recommended


```typebool operator ==(){}```


### `-` operator is overloaded twice



### Can overload as "member operator”








