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Operator << overload

//using namespace std;

using std::ifstream;

using std::ofstream;

using std::cout;

class Dog
{

    friend ostream& operator<< (ostream&, const Dog&);

    public:
        char* name;
        char* breed;
        char* gender;

        Dog();
        ~Dog();

};

im trying to overload the <operator. I am also trying to practice good coding. But my code won't compile unless I uncomment the use of the std namespace. I keep getting this error and I don't know. im using the g ++ compiler.

Dog.h:20: error: ISO C++ forbids declaration of ‘ostream’ with no type
Dog.h:20: error: ‘ostream’ is neither function nor member function; cannot be declared friend. if i add line using std::cout; then i get this error.
Dog.h:21: error: ISO C++ forbids declaration of ‘ostream’ with no type.

Can someone tell me the correct way to overload the <operator without using the std namespace;

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2 answers


You have using std::ofstream

instead using std::ostream

, so he doesn't know what it is ostream

.

You also need to enable <ostream>

.



Indeed, there is no reason to use using anything

; you should just qualify names with a namespace (especially if it's a header file so as not to pollute the global namespace of other files):

friend std::ostream& operator<< (std::ostream&, const Dog&);
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The keyword using

means you can access anything not prefixed with its namespace. In words, orter, using std::ofstream;

just says so you can access std::ofstream

how ofstream

.



You also seem to need #include <iostream>

; why the compiler doesn't know what is ostream

. Put this in, change your friend's ad to friend std::ostream& operator<< (std::ostream&, const Dog&);

and get rid of all the stuff using

, as this is a bad form to post using

in the headline and you should be fine.

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