C++ header include conflict

Question

I am working on a traffic simulation program for school. My Simulation class reads in a list of vehicles from an XML file, so I have included Vehicle.h in my Simulation class. I want my vehicle to be able to hold a pointer to the simulation object so that it can use the simulation's searchRoads function. So I included Simulation.h in my Vehicle class.

When I did this, I got over 100 errors when I tried to compile. I'm pretty iffy on my C++ so if I committed some sort of cardinal sin, please let me know how to rectify this.

1) include guards. 2) post your code. 3) not all your code, of course, just an example that shows the problem. — Kerrek SB
– Kerrek SB, Commented Jul 8, 2011 at 17:47

Alok Save · Accepted Answer · 2011-07-08 17:54:40Z

3

Either, You are missing inclusion guards, leading to multiple inclusion of header files

Or

You are creating a Circular Dependency of your headers. You should be rather using Forward Declaration.

Post details of your code for more detailed answer.

edited Jul 8, 2011 at 17:54

answered Jul 8, 2011 at 17:47

Alok Save

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3 Comments

X_X Over a year ago

I made a circular dependency. I figured it was something like that, I just didn't know what it was called. I had no idea it was as simple to fix as it was. Thank you for the links also! Code is working! :D

Alok Save Over a year ago

@X_X: Glad could I help, Do post minimalistic code sample of your problem from hereon to get quick answers and oh do accept the answer if it helped :)

X_X Over a year ago

Will do, now I need to go through all my files and get rid of these stupid mistakes.

crisbia · Accepted Answer · 2011-07-08 17:47:24Z

0

You learn something about include guards: http://en.wikipedia.org/wiki/Include_guard Hope this helps.

answered Jul 8, 2011 at 17:47

crisbia

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1 Comment

crisbia Over a year ago

good, that's usually the best practice for start!glad to see that the answer from Als helped. mine was more a shot in the dark

Jay · Accepted Answer · 2011-07-08 21:50:32Z

Since operating systems have the ability to handle long file names I've started naming my include files so they reflect the code's position in the namespace:

namespace network { class connection { bool send( char* stuff ); } }

Would end up in the file "network.connection.h".

It helps keep things organized and reduces the chance of name collision of files.

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