C++ overloading >> and<< operators

Question

fstream& operator>> (fstream & in, class& obj);

fstream& operator<< (fstream & out, class& obj);

Is this overloading legal or not?
And what is it's solution?

Actually l am using files in a program with the help of fstream class objects. So I need to overload >>&<< operators so that such statements can work.

File>>obj; File<

But would ifstream& operator >> (ifstream & , classname& obj) ofstream& operator >> (ofstream & , classname& obj)

Work for fstream objects?

`class` is a language keyword, not a type. So your examples as written are not valid C++. If you replace `class` with the name of a valid type for which `fstream` does not already overload the operators, then your examples would be valid declarations - assuming a `using namespace std` is in effect, and not causing ambiguity. — Peter, Jun 19 '18 at 06:10
Related: [What are the basic rules and idioms for operator overloading?](https://stackoverflow.com/questions/4421706/) — Remy Lebeau, Jun 19 '18 at 06:17

score 1 · Answer 1 · edited Jun 19 '18 at 06:19

1

Legal, but you should use the more general forms:

istream& operator>>(istream& in, t& obj);
ostream& operator<<(ostream& out, const t& obj);

edited Jun 19 '18 at 06:19

Remy Lebeau

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answered Jun 19 '18 at 06:04

krisz

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score 0 · Answer 2 · answered Jun 19 '18 at 06:26

In operator overloading, if an operator is overloaded as member, then it must be a member of the object on left side of the operator.The operators ‘<<' and '>>' are called like 'cout << ob1' and 'cin >> ob1'. So if we want to make them a member method, then they must be made members of ostream and istream classes, which is not a good option most of the time. Therefore, these operators are overloaded as global functions with two parameters, cout and object of user defined class.

it is better if you include an example in your answer – Ravi Mariya Jun 19 '18 at 06:52 — Ravi Mariya, Jun 19 '18 at 06:52

C++ overloading >> and<< operators

2 Answers2