Thread: including templatized vector and vector

why is it that I got this error, when I compile the code by using the -Dproject flag?:

Code:

/vehicle.h:21: error: âprojectâ has not been declared
/vehicle.h:21: error: expected `{' before âvectorâ
/vehicle.h:21: error: expected initializer before â<â token
/vehicle.h:33: error: âprojectâ has not been declared
/vehicle.h:33: error: expected `{' before âvectorâ

am I doing anything wrong? the code is attached below...
The weird thing is that if I take out the #include <vector> in the vehicle.h file and then compile the file using -Dproject it works, however if I include it with athe #include <vector> it doesn't work... I just don't know why

I recommend running it through the preprocessor only (-E with GCC), and you should find something like this:

Code:

namespace 1{

template <class type, int n> class vector;

and

Code:

class State : public 1::vector<double, 4> { };

Use a convention for macro names that doesn't let them get mixed up with other identifiers (e.g macro names and only macro names are ALL CAPS).

-----------

Another thing:

Code:

template <class type, int n>
bool checkSize(const vector<type, n>& v1, const vector<type, n>& v2)
{
   try {
      if( v1.size != v2.size )
         throw "Operations of two vectors of not the same size!";
	return true;
   }
   catch( char * str ) {
      std::cout << "Exception raised: " << str << std::endl;
   }
}

1) Don't use throw for flow control inside a function. Exceptions are thrown to indicate to the caller that something is wrong, otherwise you can just use normal flow control constructs:

Code:

template <class type, int n>
bool checkSize(const vector<type, n>& v1, const vector<type, n>& v2)
{

   if( v1.size == v2.size )
       return true;
   std::cout << "Exception raised: Operations of two vectors of not the same size!" << std::endl;
   //note the lack of return statement!?: did you mean: return false;?
}

2) Printing an error message and continuing as if nothing happened (in this case returning an indeterminate value) is not a particularly good error handling strategy. The caller will not know what happened in checkSize.

3) If you need to throw exceptions, prefer throwing exception objects (preferable one defined in <stdexcept> or derived from those) over built-in types.