Problem using a function from other file

hello Every 1

visual studio 2010.............
c++

i have a problem , i need to use a function named getentityposition which is in some file for example named AgentActioncomponent ,when i want to call this function i am available with AgentActioncomponent and even getentityposition...i call it in this way
******************************************************************
Vec3f currentPos = AgentActionComponent::getEntityPosition(m_characterID2);
******************************************************************

but it doesnt recognize AgentActionComponent .. when i take my cursor to AgentActionComponent it says non static member reference
must be relative to a specific object ....

does any body have any idea

Regards Imran Habib

Quote:

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does any body have any idea

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Exactly what the error says. The function you are calling is a non-static function, so you can only use this function when it's part of a already created object.

Code:

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AgentActionComponent myObject;

Vec3f currentPos = myObject.getEntityPosition (m_characterID2);

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Quote:

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Originally Posted by Skizmo

Exactly what the error says. The function you are calling is a non-static function, so you can only use this function when it's part of a already created object.

Code:

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AgentActionComponent myObject;

Vec3f currentPos = myObject.getEntityPosition (m_characterID2);

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1. Well ! i have tried the way u told me but when i m creating object it doesnt recognize object


To make my question more clear .........


2. the AgentActionComponent is a headerfile which has another .cpp file with the same name
the header file contains declaration about function getentityposition and .cpp file contains
definition ....

i don't know but i guess there is some connection missing some where....

Kindly help

Regards Imran Habib

Quote:

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Originally Posted by imranhabib1

1. Well ! i have tried the way u told me but when i m creating object it doesnt recognize object


To make my question more clear .........


2. the AgentActionComponent is a headerfile which has another .cpp file with the same name
the header file contains declaration about function getentityposition and .cpp file contains
definition ....

i don't know but i guess there is some connection missing some where....

Kindly help

Regards Imran Habib

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Your question is clear, your understanding of the problem isn't.

You're trying to call a non-static member function of a class. To do that, you need an instantiation of the class - an object. You're trying to call the function as if it were static and it's clearly not defined that way. It's not a header/cpp issue, it's a not calling the function properly issue.

Can you post the code where you tried to create an object?

Quote:

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Originally Posted by GCDEF

Your question is clear, your understanding of the problem isn't.

You're trying to call a non-static member function of a class. To do that, you need an instantiation of the class - an object. You're trying to call the function as if it were static and it's clearly not defined that way. It's not a header/cpp issue, it's a not calling the function properly issue.

Can you post the code where you tried to create an object?

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here we go

*****************************************
AgentActionComponent Obj;
Obj.getEntityPosition(m_characterID2);
*****************************************
it says no default constructor .............. on taking cursor to Obj .. i tried delcaring default constructor
but it doesnt work yet ...........
any suggestions

Quote:

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Originally Posted by imranhabib1

here we go

*****************************************
AgentActionComponent Obj;
Obj.getEntityPosition(m_characterID2);
*****************************************
it says no default constructor .............. on taking cursor to Obj .. i tried delcaring default constructor
but it doesnt work yet ...........
any suggestions

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Stop telling us you tried stuff and it didn't work without showing the code.

The error messages mean something. Obviously you need to create a default constructor. Show us what you did and we'll tell you why it didn't work.

Quote:

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Originally Posted by GCDEF

Stop telling us you tried stuff and it didn't work without showing the code.

The error messages mean something. Obviously you need to create a default constructor. Show us what you did and we'll tell you why it didn't work.

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AgentActioncomponent* Obj;
Obj->getentityposition;
now i dun have error but i have another problem in it and it is linking problem....
actually as far as i know if we need to access a member function in from header file we need to
1. add header .h as an header in .cpp
2. we have to call constructor of the class , (the same class whose member function we are calling) in our .cpp
3. adding refernce to .h file

I did 1 and 3 .. but i am confused about doing 2 ... because it has no default constructor I mean constructor with out parameters and its other constructor eg AgentActioncomponent(GameEntity* ABC)
can be used or not in my .cpp

Lastly :::: I CREATED my default constructor in that header file but i dun get when i call that default constructor ....

if u can help plz kindly let me know , how should i solve this prob


Directions will b appreciated

Regards Imran Habib

Quote:

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Originally Posted by imranhabib1

2. we have to call constructor of the class , (the same class whose member function we are calling) in our .cpp

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This is not true.

Quote:

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3. adding refernce to .h file

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What do you mean by "reference to .h file"?

Quote:

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I did 1 and 3 .. but i am confused about doing 2 ... because it has no default constructor I mean constructor with out parameters and its other constructor eg AgentActioncomponent(GameEntity* ABC)
can be used or not in my .cpp

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None of what you stated makes sense.

Here is an example of code where 2) is not necessary:

Code:

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#include <string>

size_t foo(std::string& s)
{
    return s.length();
}

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Where do you see a default constructor being called for s? That code will compile just fine. As for 3) in your description, I have no idea what you're referring to.

Regards,

Paul McKenzie

Quote:

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Originally Posted by imranhabib1;2005702

AgentActioncomponent* Obj;
Obj->getentityposition;

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Obj is an unitialized pointer.
Obj->getentityposition is trying to dereference an unitialized pointer which will almost always cause your program to crash.
When you call a function, you need to put parens after the function name, and include applicable arguments between the parens.

There's been a rash of people here lately trying to program by guessing. That will never work. Get a good book and work through it.

Quote:

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Originally Posted by imranhabib1

if u can help plz kindly let me know , how should i solve this prob


Directions will b appreciated

Regards Imran Habib

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We speak in complete sentences using real words on this board.

Quote:

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Originally Posted by GCDEF

There's been a rash of people here lately trying to program by guessing. That will never work.

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I guess that they believe C++ can be learned by "feel" and maybe a cheat sheet listing some commands.

Regards,

Paul McKenzie

Quote:

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Originally Posted by imranhabib1

AgentActioncomponent* Obj;
Obj->getentityposition;
now i dun have error but i have another problem in it and it is linking
problem....

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Well, actually you managed to cheat the compiler this way, and you don't have a compilation error now, but you still do have error, and linking problem is the smallest part of it. Even if you manage somehow to link that, your code is 100% going to crash at runtime because of uninitialized pointer.

Quote:

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actually as far as i know if we need to access a member function in from header file we need to
1. add header .h as an header in .cpp
2. we have to call constructor of the class , (the same class whose member function we are calling) in our .cpp
3. adding refernce to .h file

I did 1 and 3 .. but i am confused about doing 2 ... because it has no default constructor I mean constructor with out parameters and its other constructor eg AgentActioncomponent(GameEntity* ABC)
can be used or not in my .cpp

Lastly :::: I CREATED my default constructor in that header file but i dun get when i call that default constructor ....

if u can help plz kindly let me know , how should i solve this prob

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Sorry, no intention to offend anyhow. It's obvious you do not understand pointers, constructors, and something makes me believe your do-not-understand list does not end with those. And the best solution to your problem would be to go back and start learning C++ from the very beginning, get some fundamental reading on C++ and do not skip doing exercises disregarding how boring those would seem to you.