'virtual' means, 'keep a record inside the class for which function I should call'. Otherwise, the compiler doesn't know anything except the type of the variable/pointer.
For example:
Adding virtual allows it to remember that f() was overloaded / replaced. This memory takes a little space.
hi all
im working in tcsh shell.
In sh shell i write for example:
case in $www
1 | 2 | 3)
arguments;;
4 | 5 | 6)
arguments;;
esac
can anybody tell me the equivalent to tcsh of
1 | 2 | 3)? (2 Replies)
Hi,
I have a base class and derived a class from the base class, i want to print & read the data for the object created for the derived class,so i have overloaded both the << and >> operators and also have done the foward declaration.
Below is the code snippet,
#include <iostream>
class... (3 Replies)
is it possible to use multiple conditions in a CASE statement? And if so, what is the syntax? I'm trying to use one but can't seem to get it right. I want the statement to be
CASE $vendor OR $alias
condition 1) statements;
condition 2) statements;
etc.
esac
but I keep... (25 Replies)
Hi all,
I am attempting to create a shell script to optimize some routine process.
I want this script can let user select the actions they want to do.
But I met a problem that my script can only read one input and then do one action.
Is it possible to let my script to run more than one... (2 Replies)
Hi all!
I am trying to register a device in an existing device class, but I am
having trouble getting the pointer to an existing class.
I can create a class in a module, get the pointer to it and then use
it to register the device with:
*cl = class_create(THIS_MODULE, className);... (0 Replies)
Hi,
In multi-level inheritance:
class A {
public:
void fun() { cout << "A" << endl; }
};
class B : public A {
public:
void fun() { cout << "A" << endl; }
};
class C : public B { };
int main() {
C c;
c.fun(); // Ans: A
} (1 Reply)
I have the two class definition as follows.
class A { public: int a; };
class B : virtual public A{ };
The size of class A is shown as 4, and size of class B is shown as 16. Why is this effect ?. (2 Replies)
Hello All,
I am a learner in C++. I was testing my inheritance knowledge with following piece of code.
#include <iostream>
using namespace std;
class base
{
public :
void display()
{
cout << "In base display()" << endl;
}
void display(int k)
{... (2 Replies)
Discussion started by: anand.shah
2 Replies
LEARN ABOUT HPUX
creator
Creator(3U) InterViews Reference Manual Creator(3U)NAME
Creator - recreates catalog-managed objects from disk and instantiates component views from their class identifiers
SYNOPSIS
#include <Unidraw/creator.h>
DESCRIPTION
A creator object can reconstruct a catalog-managed object from disk and can instantiate a component view given a class identifier. Gener-
ally only the Catalog class uses the creator to reconstruct objects from disk, but it may be useful for other classes (e.g., the Component
base class) to use the creator to create views of component subjects.
Applications that derive new catalog-managed classes or component views must also derive a subclass of Creator that extends the base class
operations to support the new classes.
PUBLIC OPERATIONS
Creator()
Instantiate an new creator object. The Catalog constructor requires an instance of a creator object, either an instance of the Cre-
ator base class or an instance of an application-specific Creator subclass.
virtual void* Create(
ClassId, istream& in, ObjectMap* objmap, int objid
)
Create an instance of the class corresponding to the given class identifier. Normally this operation will be used by the Catalog
class exclusively. This operation contains a switch statement that calls a CREATE macro for each possible class identifier. The
CREATE macro takes the istream, ObjectMap, and int arguments as parameters; it is not important to understand how the macro uses
these arguments. For example, the entry for the LineComp line component subject class is
case LINE_COMP: CREATE(LineComp, in, objmap, objid);
Derived Creator classes must redefine this operation to include a switch statement for application-specific classes, with the
default case calling the parent class's Create operation.
virtual void* Create(ClassId id)
Create an instance of the view class corresponding to the given view class identifier. This operation is implemented with a set of
consecutive if statements of the form
if (id == <identifier name>) return new <class name>;
For example, the entry for the PostScript external view class identifier for line components is
if (id == PS_LINE) return new PSLine;
Derived Creator classes must redefine this operation to include if statements for application-specific view classes, with the final
statement being a call to the parent classes's Create operation.
SEE ALSO Catalog(3U), classes(3U), globals(3U)Unidraw 12 June 1990 Creator(3U)