Re: working with pointers
- From: Shane Hathaway <shane@xxxxxxxxxxxxxxx>
- Date: Tue, 31 May 2005 14:56:59 -0600
Michael wrote:
> sorry, I'm used to working in c++ :-p
>
> if i do
> a=2
> b=a
> b=0
> then a is still 2!?
>
> so when do = mean a reference to the same object and when does it mean make
> a copy of the object??
To understand this in C++ terms, you have to treat everything, including
simple integers, as a class instance, and every variable is a reference
(or "smart pointer".) The literals '0' and '2' produce integer class
instances rather than primitive integers. Here's a reasonable C++
translation of that code, omitting destruction issues:
class Integer
{
private:
int value;
public:
Integer(int v) { value = v; }
int asInt() { return value; }
}
void test()
{
Integer *a, *b;
a = new Integer(2);
b = a;
b = new Integer(0);
}
In that light, do you see why a is still 2?
Shane
.
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