Problem with Polygon in Stroustrup's PPP book

[ariao...@gmail.com]

Hi guys,

I read Programming Principles and Practice using C++, Stroustrup's book. In chapter 12 and in page 441 (first example) there is this code:

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// // This is example code from Chapter 12.3 "A first example" of // "Programming -- Principles and Practice Using C++" by Bjarne Stroustrup // #include "Simple_window.h" // get access to our window library #include "Graph.h" // get access to our graphics library facilities //------------------------------------------------------------------------------ int main() { using namespace Graph_lib; // our graphics facilities are in Graph_lib Point tl(100,100); // to become top left corner of window Simple_window win(tl,600,400,"Canvas"); // make a simple window Polygon poly; // make a shape (a polygon) poly.add(Point(300,200)); // add a point poly.add(Point(350,100)); // add another point poly.add(Point(400,200)); // add a third point poly.set_color(Color::red); // adjust properties of poly win.attach (poly); // connect poly to the window win.wait_for_button(); // give control to the display engine } //------------------------------------------------------------------------------

When I run the code I get 13 errors which must of them are about the Polygon identifier. 
The problem in that code has to do with Polygon poly; and the rest of the using of it. For example first error is: Error C2872: 'Polygon' : ambiguous symbol

Why my compiler doesn't know that Polygon please?

[corn...@google.com]

On Wednesday, January 8, 2014 8:52:28 AM UTC+1, ariao...@gmail.com wrote:

Hi guys,

Why my compiler doesn't know that Polygon please?

Hi,

This forum is for discussing the C++ standard. Help with programming is better suited for http://stackoverflow.com and issues with books should be directed to the book's publisher or author.

That said, your compiler does know Polygon. In fact, it knows more than one; that's what "ambiguous" means. It just doesn't know which you mean. You'll have to find out where the other one comes from. (The compiler should be telling you, actually. See if there are any notes after that error.)

Sebastian

[ariao...@gmail.com]

I stated this problem in stackoverflow.com, but no one could tell me a solution so I decided to state it here. All the code is that I've mentioned in my first post. I just run it and it gives me 13 errors. the first is:

Error 8 error C2872: 'Polygon' : ambiguous symbol c:\users\cs\documents\visual studio 2012\projects\testv\testv\testv.cpp 19

and for example next error is this: Error 9 error C2146: syntax error : missing ';' before identifier 'poly' c:\users\cs\documents\visual studio 2012\projects\testv\testv\testv.cpp 19

As you see almost all the errors are about that Polygon. If it help I write all the errors. I don't know where there is another one of that Polygon with the same name and I love to know to get rid of this problem.

And about the Author, what can I do if he doesn't reply?

[corn...@google.com]

On Wednesday, January 8, 2014 1:35:45 PM UTC+1, ariao...@gmail.com wrote:

I stated this problem in stackoverflow.com, but no one could tell me a solution so I decided to state it here.

It's still an inappropriate forum. Having tried an appropriate one first doesn't make it any more appropriate.

If the compiler doesn't tell you, generate the preprocessed code (there's always a switch for that) and do a text search for Polygon.

[Vlad from Moscow]

If the compiler reports that there is an ambiguous symbol then it also points out where this symbol id declared. So it would be more useful if you would show the complete error message.

 

Also take into account that header "Simple_window.h" already include header "Graph.h". So there is no any need in directive #include "Graph.h".

 

All headers used in this chapter can be downloaded from here

 

http://www.stroustrup.com/Programming/Graphics/

 

You can check whether your headers are not corrupted.

 

 

среда, 8 января 2014 г., 11:52:28 UTC+4 пользователь ariao...@gmail.com написал:

[ariao...@gmail.com]

How to generate preprocessed code?

[Vlad from Moscow]

Also you can try to specify qualified name. For example

 

Graph_lib ::Polygon poly;

среда, 8 января 2014 г., 18:00:04 UTC+4 пользователь Vlad from Moscow написал:

[ariao...@gmail.com]

Everything is mixed now. I'm going to remove the compiler and the reinstall it again and do works from beginning. 

[Vlad from Moscow]

Before doing so try to do as I suggested that is try to use the qualified name.

среда, 8 января 2014 г., 18:31:30 UTC+4 пользователь ariao...@gmail.com написал:

[ariao...@gmail.com]

I used this snip code Graph_lib::Polygon poly; instead of this Polygon poly; and ran the code again. Again there were 11 errors, first is this:

Error    9          error LNK2001: unresolved external symbol "protected: virtual void __thiscall Graph_lib::Window::draw(void)" (?draw@Window@Graph_lib@@MAEXXZ)            C:\Users\CS\documents\visual studio 2012\Projects\Win32Project1\Win32Project1\Win32Project1.obj

[ariao...@gmail.com]

Any more opinion?