Re: comp.language, c++
On Wednesday, 13 March 2013 11:45:57 UTC+2, Monis Khan wrote:
Hello every one
I am working on a project which involve run-time polymorphism and writing
data in files. I have created an abstract class and 4 other classes
deriving the base class(derived class). here is it like
I hope it is school assignment, otherwise with such a level of knowledge
you will be kicked far from that "project".
class prdcts
{
virtual void enter()=0;
}
Size of this class is very little. Basically pointer to virtual functions
table.
4 classes deriving from this base class. In main I created option like this
Oh! You think that those 4 are least important for the problem?
void main()
{
//other codes
if(ch==1)
{
class a;
Forward-declaring a class here?
deploy(&a);
You can not take pointer to a class. You need object.
}
// other codes
}
void deploy(prdcts *p)
{
fstream filee;
filee.open("demao.dat",ios::out|ios::binary);
You do not check how it went?
p->enter();
what that does?
filee.write((char*)&p,sizeof(p));
You take pointer to base class convert pointer to that pointer
into char pointer and write to file?
//other codes
}
when I am writing this no data is written in the file, plz help me out
with correct syntax and explaintaion for writing in file through pointer
of base class
Fuzzy pointer magics that wizards like us will suggest do not exist. You
need to write code that does exactly what the program must do. You need
virtual function in each derived class that writes data of it to file.
'enter()' does not sound like one so add another.