How to define a template specialization for a friend function or operator?

Question

I wish to overload a friend function or a friend operator in a different way for a data type.
How can I achieve the same ?

Answer 1

need to be able to bookmark posts on the phone. i know i will need to do this one day

Answer 2

Nice Idea. And whilst I am here..

Kinshuk: Well done! I had faith in you the whole time!

Answer 3

No Eye Deer.. But does this help?
http://stackoverflow.com/questions/4421706/operator-overloading

Answer 4

p.s when you find out? can you share a code example with comments? cause you know, you are awesome!

Answer 5

@‎ɐısıօլɐ
It is finally done!
I finally completed it!

This is what I used:

// Forward declare the class
template <class M>
class Matrix;

// Forward declare the template operator
template <typename M>
ostream& operator<<(ostream& out, const Matrix<M>& matrix);

// Forward declare the function
ostream& operator<<(ostream& out, const Matrix<Complex>& mc);

//Now the Matrix Class :

template<class M>
class Matrix
{
//Many useful Functions...
friend std::ostream& operator<<(std::ostream& out, const Matrix<Complex>& matrix ) //Function Specialization
{
for(int i=0;i<mc.r;i++)
for(int j=0;j<mc.c;j++)
{
cout<<"Element at "<<i<<","<<j<<" - "<<mc.mat[i][j]<<endl;
}
}
friend std::ostream& operator<< <>(std::ostream& out, const Matrix<M>& matrix ) //Original Template Overload...
{
for(int i=0;i<matrix.r;i++)
for(int j=0;j<matrix.c;j++)
cout<<matrix.mat[i][j];
}
}

Thanks a Ton for your help!

Answer 6

Yes, as anyone would prefer << over a print function in C++ atleast...

Answer 7

I really forgot the & in the specialization 😅.
But on putting it, i am left with just the second error I mentioned before...

Answer 8

So one must force declare the class and its function for specializations...

Yes, it must be made as an instance...

Answer 9

:) aloisia is smart too! but you never gave up either

Answer 10

Yes, making a print function and overloading works, but only if its not a friend...
I guess Ill have to adjust with the print function for this task...

Answer 11

well the first error says you should've written template<class T> before the operator<< declaration, I don't know if that'll work though if it is inside the Matrix class

Answer 12

Why is that required though when there is template<class M> before the class?

Answer 13

or I just saw a solution on stack overflow that looks like this, maybe it'll work for you?
friend ostream& operator<< <T>(ostream& o, const Matrix<T>& mat)

Answer 14

Ill try it then...

Answer 15

that's required because it is not a method of the class Matrix but just a friend function and you can't specialize the function over the class Matrix, because it is not an instance of it

Answer 16

It didn't work...
Perhaps I am not able to implement it as said...

Answer 17

Amazing, I'm glad I could help you :D Cheers! 🍻

Answer 18

@jay maybe share the link to the discussion to yourself and copy it into a memo :D

Answer 19

@jay
Sorry, but that didn't help as its just a detailed explanation for operator overloading...

I want to know how I can overload the friend operators or functions of a template class for a data type like double or char...

Answer 20

@jay
Sorry, but that didn't help...

I wish to know a way so I can overload a friend function of a template class for a particular data type like double or char.