Using "object<(ostream)"

Asked Jun 10 '17 at 09:50

Active Jun 10 '17 at 10:14

Viewed 26 times

I know that << operator can be overloaded as method function as well. The problem comes when i am using template arguments.

I've realised that i need to specify the class and as such i wrote < A > before operator<< .

Where should i write < A > if i want to use the object< < ostream syntax ?

#include <iostream>
#include <malloc.h>

using namespace std;



class A
{
private:
    int x;

public :

A(int i = 0)
{
    x = i;

}
A operator + (A temp)
{
    return x + temp.x;
}

template <class T>
ostream & operator << (ostream &);
};

template <class T>
ostream& A::operator<<(ostream &o)
{
o<<x;
return o;

}

int main()
{
A a(33),b(-21);
(a+b).operator<<<A>(cout);
//a+b<<cout; ????
}

edited Jun 10 '17 at 10:14

asked Jun 10 '17 at 09:50

Eduard6421

You need to overload a free standing binary operator funtion for stream output.behavior. – πάντα ῥεῖ Jun 10 '17 at 09:56
Either the template-parameters are deduced by the type of a parameter, or you should write (...).operator <<(...) always. Why do you want to use cout as the right parameter, while you normally shift the things from the right into the stream? – cmdLP Jun 10 '17 at 09:58
Is there any need for the template parameter? – chtz Jun 10 '17 at 09:59
No, there is no actual need for it. I'm using it as a template because i want to accommodate with using template parameters. – Eduard6421 Jun 10 '17 at 10:06
Just don't use template for operators (unless they can be deduced by the passed types). Otherwise, `(a+b).operator<< (cout);` is essentially the only way to call that operator. – chtz Jun 10 '17 at 10:44

Using "object<(ostream)"

0 Answers0