No match for operator error.

[snphilosopher]

This is a code I am trying to run from C++ Primer by Lippman. However, I am getting this error in line 12. No match for operator in "std::cin>>item1"

 
#include <iostream>
#include "Sales_item.h"

using namespace std;

int main()
{


    Sales_item item1, item2;
    std::cin>>item1>>item2;
    std::cout<<item1+item2<<std::endl;

    return 0;

[wildblue]

Does Sales_item.h have an overload in the Sales_item class for the >> operator?

[snphilosopher]

Thanks! I do not exactly how to check it. This is all the content I have on the .h file. (it was automatically generated).

#ifndef SALES_ITEM_H_INCLUDED
#define SALES_ITEM_H_INCLUDED



#endif // SALES_ITEM_H_INCLUDED 

[wildblue]

So the header file has no actual content? Where is the class Sales_item defined?


Edit:
There's a section on operator overloads in the tutorial here. If you have a user defined type like a Sales_item class - you need to define how an operator like << should work.

http://www.cplusplus.com/doc/tutorial/templates/

[Chervil]

But if the header file has no actual content, line 11 could not compile:

    Sales_item item1, item2;

There must be a more complete version of "Sales_item.h" somewhere?

[snphilosopher]

Wildblue and Chervil:

Thank you for your answers. The problem is that the book does not explicitly indicates how to do that previously.

For example I do not know if I need to create the header file and also the class.

Is there a book or tutorial where I can learn how to define these things?

[wildblue]

I don't have the Lippman book, but I've got to think that a primer on C++ would include classes. What does the book say this particularly code snippet is trying to help illustrate?

You can get into the tutorial on this site through that link I posted above.

[Chervil]

When I tried to compile that code, i got the following errors:

[Error] 'Sales_item' was not declared in this scope
[Error] expected ';' before 'item1'
[Error] 'item1' was not declared in this scope
[Error] 'item2' was not declared in this scope

That is to say, it fails before reaching line 12.
Does your compiler also give similar errors?

[snphilosopher]

Yes. The second one. The problem is that I do not know what kind of code to write on the.h file. I will be searching on the web.

[Chervil]

Well, it seems as though either the book hasn't explained things very clearly, or perhaps that code wasn't meant to be a complete runnable program, it was just to read through and then move on. Or maybe the book comes with a cd or web site where you can get the full cpp code.