shallow copy
-----------------
class MyString {
char *str;
public:
MyString(char *);
//MyString & operator=(const MyString & t);
};
MyString :: MyString(char *)
{
}
MyString a("rahul");
MyString b;
b = a;
the default = operator does a bitwise copy, so if we don't overload the
default behaviour, it will just copy the contents of a to b. so now both a &
b will point to the same memory.
this is shallow copy. nd it hs memory issues due to obvious reasons.
deep copy
---------------
a deep copy of a to b, should allocate memory for b nd den should copy the
value of a to b.
so, now both the objects have distinct memory allocated to it. So, ther wont
be memory related issues here.
to do deep copy, we need to overload the default behavior of the assignment
operator.
MyInt & MyInt :: operator=(const MyInt & t);
{
}
now, wen u do
b= a
instead of memory there may be any resource which 2 objects shouldn't
share.
On Sun, Oct 2, 2011 at 2:21 AM, rahul sharma <rahul23111...@gmail.com>wrote:
> means if i use like
>
> main()
> {
> int *ptr;
> abc(ptr);
> }
> abc(int *a)
> {
> }
> this is shallow copy
> m i ryt???
> if yes thne tell xample of deep shallow..otherwise give me examples
> regarding c++....cozxamples clear everythng
>
>
> On Sun, Oct 2, 2011 at 11:00 AM, megha agrawal <megha14.2...@gmail.com>wrote:
>
>> One function passes a pointer to the value of interest to another
>> function. Both functions can access the
>> value of interest, but the value of interest itself is not copied. This
>> communication is
>> called shallow. The alternative where a complete copy is made and sent is
>> known as a "deep"
>> copy.
>>
>> On Sat, Oct 1, 2011 at 7:36 PM, rahul sharma <rahul23111...@gmail.com>wrote:
>>
>>> plz give any c++ xample to xplain bit more
>>>
>>>
>>> On Sat, Oct 1, 2011 at 6:59 PM, Bejoy kalikotay(sikkimesechora....) <
>>> bijaykaliko...@gmail.com> wrote:
>>>
>>>> A shallow copy of an object copies all of the member field values.
>>>> This works well if the fields are values, but may not be what you want
>>>> for fields that point to dynamically allocated memory. The pointer
>>>> will be copied. but the memory it points to will not be copied -- the
>>>> field in both the original object and the copy will then point to the
>>>> same dynamically allocated memory, which is not usually what you want.
>>>> The default copy constructor and assignment operator make shallow
>>>> copies.
>>>>
>>>> A deep copy copies all fields, and makes copies of dynamically
>>>> allocated memory pointed to by the fields. To make a deep copy, you
>>>> must write a copy constructor and overload the assignment operator,
>>>> otherwise the copy will point to the original, with disasterous
>>>> consequences.
>>>>
>>>> On Oct 1, 4:50 pm, rahul sharma <rahul23111...@gmail.com> wrote:
>>>> > plz xpalin waht is deep and shallow copy in c++
>>>>
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