I am not familiar with the pr
 

I am not familiar with the programming art of OpenFOAM,yet. Today, I add a few lines in the 'main' function as follows:
1. scalar dalp,alp;
2. dalp=cos(alp);

But when I run 'wmake',the error is "call of overloaded `cos(Foam::scalar&)' is ambiguous".

What should I do? By the way,what are the main special features for OpenFOAM, compared to the original C/C++?

Thanks.

try dalp=Foam::cos(alp)
 

try dalp=Foam::cos(alp)