Thread: including my extras.h file. errors

Hi. I'm having some issues with compiling my program. I have several files: hw4-ffnn.cpp, network.{h,cpp}, neuron.{h,cpp}, and an extras.h file with a struct and some typedefs that I want common to all my files.
Here's my extras.h file:

Code:

#ifndef _extras_h_
#define _extras_h_

#include <vector>
#include <string>

struct input_node{
	bool training;
	vector<int> pattern, target;
};

typedef vector<input_node> input;
typedef vector< vector<int> > data;

#endif

I'm getting some inconsistent results when I use the g++ compiler with a few different options:

Code:

g++ hw4-ffnn.cpp -o hw4

works fine (actually, i get some linking errors, but I don't think that they are relevant to this issue).
However, when I do

Code:

g++ -c neuron.cpp network.cpp hw4-ffnn.cpp

I get some errors:

Code:

extras.h:10: error: ISO C++ forbids declaration of 'vector' with no type
extras.h:10: error: expected ';' before '<' token
extras.h:13: error: expected initializer before '<' token
extras.h:14: error: expected initializer before '<' token
neuron.h:16: error: ISO C++ forbids declaration of 'data' with no type
neuron.h:16: error: expected ';' before '*' token
neuron.h:27: error: 'data' has not been declared
neuron.cpp:15: error: variable or field 'set_weights' declared void
neuron.cpp:15: error: 'int Neuron::set_weights' is not a static member of 'class Neuron'
neuron.cpp:15: error: 'data' was not declared in this scope
neuron.cpp:15: error: 'w' was not declared in this scope
neuron.cpp:15: error: expected ',' or ';' before '{' token
extras.h:10: error: ISO C++ forbids declaration of 'vector' with no type
extras.h:10: error: expected ';' before '<' token
extras.h:13: error: expected initializer before '<' token
extras.h:14: error: expected initializer before '<' token
neuron.h:16: error: ISO C++ forbids declaration of 'data' with no type
neuron.h:16: error: expected ';' before '*' token
neuron.h:27: error: 'data' has not been declared
network.h:15: error: 'data' was not declared in this scope
network.h:15: error: template argument 1 is invalid
network.h:15: error: template argument 2 is invalid
network.h:22: error: 'input' does not name a type
network.h:27: error: expected `)' before '&' token
network.cpp:4: error: expected `)' before '&' token
network.cpp: In member function 'bool Network::category_exists(input_node&)':
network.cpp:32: error: 'input_layer' was not declared in this scope
network.cpp:33: error: 'struct input_node' has no member named 'target'
make: *** [compile] Error 1

Any ideas about what I'm missing?

Originally Posted by King Mir

use std::vector<type>.

Actually, that didn't fix the issue, but I tried adding a

Code:

using namespace std;

to the top and it worked. Also, that fixed the linking error that I mentioned.
Thanks.

Never use using-directives or using-declarations in header files, since they contaminate any file that includes the header file. Use std:: instead as King Mir suggested. What may be happening is that you have the same problem in your .cpp files, and it's relatively okay to use using-directives or using-declarations in those, though only sparingly if at all.

Originally Posted by robatino

Never use using-directives or using-declarations in header files, since they contaminate any file that includes the header file. Use std:: instead as King Mir suggested. What may be happening is that you have the same problem in your .cpp files, and it's relatively okay to use using-directives or using-declarations in those, though only sparingly if at all.

I appreciate the tip. Is this what you are talking about?

Code:

#ifndef _extras_h_
#define _extras_h_

#include <vector>
#include <string>

using std::vector;

struct input_node{
	bool training;
	vector<int> pattern, target;
};

typedef vector<input_node> input;
typedef vector< vector<int> > data;

#endif

Code:

using namespace std;

is a using-directive.

Code:

using std::vector;

is a using-declaration. Don't use either one in header files, since either one contaminates any file that includes the header file. Use std::vector explicitly in your header file (since you only have to use it 4 times in your header file, it probably doesn't even take up more space than the one "using std::vector;" does anyway, and if you aren't even saving space, why bother?).

Originally Posted by laserlight

By the way, names that begin with an underscore followed by a lower case letter are reserved to the implementation for use in the global namespace.

Are you sure?

Originally Posted by Some C++ draft

17.4.3.1.2 Global names [global.names]
1 Certain sets of names and function signatures are always reserved to the implementation:
— Each name that contains a double underscore _ _ or begins with an underscore followed by an uppercase letter
(2.11) is reserved to the implementation for any use.
— Each name that begins with an underscore is reserved to the implementation for use as a name in the global
namespace.169)

should that really keep me from using that names for myself?

Code:

::_funny_func();              // the global ns function
myns::_funny_func();     // my own implementation

That's that namespaces are for, so names don't collide?

Yes, I should really look these things over first. heh.

Code:

#ifndef _extras_h_
#define _extras_h_

#include <vector>
#include <string>

struct input_node{
	bool training;
	vector<int> pattern, target;
};

typedef vector<input_node> input;
typedef vector< vector<int> > data;

#endif

Any ideas about what I'm missing?[/QUOTE]

input_node is not a type within the vector. Try doing this:

Code:

typedef struct input_node{
	bool training;
	vector<int> pattern, target;
}input_node;

It should work. Good luck.