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Darío Alejandro Guzik
Guest
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 Posted: Tue Dec 05, 2006 7:39 pm Post subject: question about reference variables |
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Hi all!
I have a program I'm working on that has a lot of classes with members
that are references to let's say global instances of other classes.
my problem is that We detected a problem and I don't know an easy way to
solve it.
Example:
class T1 {
...
}
class T2 {
T1& val;
...
operator= (const T2 & src) { val = src.val;....};
}
the problem is that when I assign val from another instance of T2 I want
it to reference the original value, and not the local variable of the
other T2 instance.
Some simple practical example:
int main(int argc, char* argv[])
{
int a = 8;
int &b = a; //b references a value
int &c = b; //c references b value, but I want it to reference
directly a
b = 5; //this is my problem, when b changes, c changes as well
because c is referencing b and not a
return 0;
}
Is there a way to implement this without using pointers?
Thanks |
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Vladimir Grigoriev
Guest
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| Posted: Tue Dec 05, 2006 8:08 pm Post subject: Re: question about reference variables |
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In your example int a, b, c reference the same memory address. So if you
will change b, a and c will be changed also.
Vladimir Grigoriev
"Darío Alejandro Guzik" <dguzik (AT) papyro (DOT) com> wrote in message
news:4575766f (AT) newsgroups (DOT) borland.com...
| Quote: | Hi all!
I have a program I'm working on that has a lot of classes with members
that are references to let's say global instances of other classes.
my problem is that We detected a problem and I don't know an easy way to
solve it.
Example:
class T1 {
...
}
class T2 {
T1& val;
...
operator= (const T2 & src) { val = src.val;....};
}
the problem is that when I assign val from another instance of T2 I want
it to reference the original value, and not the local variable of the
other T2 instance.
Some simple practical example:
int main(int argc, char* argv[])
{
int a = 8;
int &b = a; //b references a value
int &c = b; //c references b value, but I want it to reference
directly a
b = 5; //this is my problem, when b changes, c changes as well
because c is referencing b and not a
return 0;
}
Is there a way to implement this without using pointers?
Thanks |
|
|
| Back to top |
|
|
Darío Alejandro Guzik
Guest
|
| Posted: Tue Dec 05, 2006 8:20 pm Post subject: Re: question about reference variables |
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|
Ok... I missed that... it makes sense but... is there a way to
re-initialize a reference or once assigned it is fixed, I mean, b will
always reference the memory adress of a or I can change it somehow?
Now refreshing my brains I kind of remember that reference variables in
c must be initialized on creation and cannot be modified (the L
value)... is it right?
Vladimir Grigoriev wrote:
| Quote: | In your example int a, b, c reference the same memory address. So if you
will change b, a and c will be changed also.
Vladimir Grigoriev
"Darío Alejandro Guzik" <dguzik (AT) papyro (DOT) com> wrote in message
news:4575766f (AT) newsgroups (DOT) borland.com...
Hi all!
I have a program I'm working on that has a lot of classes with members
that are references to let's say global instances of other classes.
my problem is that We detected a problem and I don't know an easy way to
solve it.
Example:
class T1 {
...
}
class T2 {
T1& val;
...
operator= (const T2 & src) { val = src.val;....};
}
the problem is that when I assign val from another instance of T2 I want
it to reference the original value, and not the local variable of the
other T2 instance.
Some simple practical example:
int main(int argc, char* argv[])
{
int a = 8;
int &b = a; //b references a value
int &c = b; //c references b value, but I want it to reference
directly a
b = 5; //this is my problem, when b changes, c changes as well
because c is referencing b and not a
return 0;
}
Is there a way to implement this without using pointers?
Thanks
|
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|
| Back to top |
|
|
Vladimir Grigoriev
Guest
|
| Posted: Tue Dec 05, 2006 8:24 pm Post subject: Re: question about reference variables |
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|
You cannot reassign a reference. Once a reference is declared it reference
the same memory during its life.
Vladimir Grigoriev
"Darío Alejandro Guzik" <dguzik (AT) papyro (DOT) com> wrote in message
news:45757ffe (AT) newsgroups (DOT) borland.com...
| Quote: | Ok... I missed that... it makes sense but... is there a way to
re-initialize a reference or once assigned it is fixed, I mean, b will
always reference the memory adress of a or I can change it somehow?
Now refreshing my brains I kind of remember that reference variables in
c must be initialized on creation and cannot be modified (the L
value)... is it right?
Vladimir Grigoriev wrote:
In your example int a, b, c reference the same memory address. So if you
will change b, a and c will be changed also.
Vladimir Grigoriev
"Darío Alejandro Guzik" <dguzik (AT) papyro (DOT) com> wrote in message
news:4575766f (AT) newsgroups (DOT) borland.com...
Hi all!
I have a program I'm working on that has a lot of classes with members
that are references to let's say global instances of other classes.
my problem is that We detected a problem and I don't know an easy way to
solve it.
Example:
class T1 {
...
}
class T2 {
T1& val;
...
operator= (const T2 & src) { val = src.val;....};
}
the problem is that when I assign val from another instance of T2 I want
it to reference the original value, and not the local variable of the
other T2 instance.
Some simple practical example:
int main(int argc, char* argv[])
{
int a = 8;
int &b = a; //b references a value
int &c = b; //c references b value, but I want it to reference
directly a
b = 5; //this is my problem, when b changes, c changes as well
because c is referencing b and not a
return 0;
}
Is there a way to implement this without using pointers?
Thanks
|
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Darío Alejandro Guzik
Guest
|
| Posted: Tue Dec 05, 2006 8:37 pm Post subject: Re: question about reference variables |
|
|
thanks... I was realizing that while asking... sometimes it helps :P
Thanks again
Vladimir Grigoriev wrote:
| Quote: | You cannot reassign a reference. Once a reference is declared it reference
the same memory during its life.
Vladimir Grigoriev
"Darío Alejandro Guzik" <dguzik (AT) papyro (DOT) com> wrote in message
news:45757ffe (AT) newsgroups (DOT) borland.com...
Ok... I missed that... it makes sense but... is there a way to
re-initialize a reference or once assigned it is fixed, I mean, b will
always reference the memory adress of a or I can change it somehow?
Now refreshing my brains I kind of remember that reference variables in
c must be initialized on creation and cannot be modified (the L
value)... is it right?
Vladimir Grigoriev wrote:
In your example int a, b, c reference the same memory address. So if you
will change b, a and c will be changed also.
Vladimir Grigoriev
"Darío Alejandro Guzik" <dguzik (AT) papyro (DOT) com> wrote in message
news:4575766f (AT) newsgroups (DOT) borland.com...
Hi all!
I have a program I'm working on that has a lot of classes with members
that are references to let's say global instances of other classes.
my problem is that We detected a problem and I don't know an easy way to
solve it.
Example:
class T1 {
...
}
class T2 {
T1& val;
...
operator= (const T2 & src) { val = src.val;....};
}
the problem is that when I assign val from another instance of T2 I want
it to reference the original value, and not the local variable of the
other T2 instance.
Some simple practical example:
int main(int argc, char* argv[])
{
int a = 8;
int &b = a; //b references a value
int &c = b; //c references b value, but I want it to reference
directly a
b = 5; //this is my problem, when b changes, c changes as well
because c is referencing b and not a
return 0;
}
Is there a way to implement this without using pointers?
Thanks
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Thomas Maeder [TeamB]
Guest
|
| Posted: Tue Dec 05, 2006 10:40 pm Post subject: Re: question about reference variables |
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|
Please direct your browser at http://info.borland.com/newsgroups/ and
read the newsgroup guidelines. One of them asks us not to quote entire
posts we are following up to; instead, please trim the quotes to the
parts relevant for your reply. Thanks! |
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Darío Alejandro Guzik
Guest
|
| Posted: Tue Dec 05, 2006 10:51 pm Post subject: Re: question about reference variables |
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sorry
Thomas Maeder [TeamB] wrote:
| Quote: | Please direct your browser at http://info.borland.com/newsgroups/ and
read the newsgroup guidelines. One of them asks us not to quote entire
posts we are following up to; instead, please trim the quotes to the
parts relevant for your reply. Thanks! |
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