C++Talk.NET Forum Index C++Talk.NET
C++ language newsgroups
 
Archives   FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Type conversion function for user defined type...

 
Post new topic   Reply to topic    C++Talk.NET Forum Index -> C++ language (comp.lang.c++)
View previous topic :: View next topic  
Author Message
Guest
PostPosted: Wed May 16, 2007 9:11 am    Post subject: Type conversion function for user defined type... Reply with quote


I have a question about type conversion function for user defined
type.

I have two classes

class DRect
{
private :
double x0;
double y0;
double x1;
double y1;
public :
DRect(double a, double b, double c, double d) : x0(a), y0(b),
x1(c), y1(d) {}
void Union(DRect* p)
{
x0 = MIN(x0, p->x0);
y0 = MIN(y0, p->y0);
x1 = MAX(x1, p->x1);
y1 = MAX(y1, p->y1);
}
}

class IRect
{
private :
int x0;
int y0;
int x1;
int y1;
public :
IRect(int a, int b, int c, int d) : x0(a), y0(b), x1(c), y1(d) {}
}


And I want to do something like this.

{
DRect d(3.4, 2.6, 19.2, 93.2);
IRect i(10, 10, 100, 100);

d.Union(i);
// or
d.Union(&i)
}


Is it possible to make a such type conversion fuction -
IRect::operator DRect() or IRect::operator DRect*()?

Thanks in advance.
Back to top
Sylvester Hesp
Guest
PostPosted: Wed May 16, 2007 9:11 am    Post subject: Re: Type conversion function for user defined type... Reply with quote


<zaeminkr (AT) gmail (DOT) com> wrote in message
news:1179301834.835559.212730 (AT) n59g2000hsh (DOT) googlegroups.com...
Quote:
I have a question about type conversion function for user defined
type.

I have two classes

class DRect
{
private :
double x0;
double y0;
double x1;
double y1;
public :
DRect(double a, double b, double c, double d) : x0(a), y0(b),
x1(c), y1(d) {}
void Union(DRect* p)

You want to accept a const DRect here, as you're not interested in changing
it (and therefore you don't need the restriction of the passed DRect being
non-const). You probably also want to accept a reference rather than a
pointer - passing 0 is pretty pointless (no pun intended Wink), and it makes
the use of the class a lot easier (no need for the & everywhere, plus you
can pass temporaries and such)


Quote:
And I want to do something like this.

{
DRect d(3.4, 2.6, 19.2, 93.2);
IRect i(10, 10, 100, 100);

d.Union(i);
// or
d.Union(&i)
}


Is it possible to make a such type conversion fuction -
IRect::operator DRect() or IRect::operator DRect*()?

Of course, but you obviously already know the syntax, so what's the problem?
class IRect
{
// ...
public:
operator DRect() const { return DRect(x0, y0, x1, y1); }
};

Now you can use d.Union(i);

- Sylvester
Back to top
Post new topic   Reply to topic    C++Talk.NET Forum Index -> C++ language (comp.lang.c++) All times are GMT
Page 1 of 1

 
  


Powered by phpBB © 2001, 2006 phpBB Group