what are the difference between the following 4 variables?
const int * start
int* const start
int const& start
Request(int const& start);
const int * start
int* const start
int const& start
Request(int const& start);
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Re: pointer vs reference
Eric Kaplan wrote:Read right to left.what are the difference between the following 4 variables?
start is a pointer to an int that is constant (the int doesn't change).const int * start
start is a constant pointer to an int (the pointer doesn't change)int* const start
start is a reference to a constant int (the int doesn't change).int const& start
start is a reference to a constant int (the int doesn't change).Request(int const& start);
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Jim Langston
tazmaster@rocke tmail.com
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Re: pointer vs reference
I suppose the following is exact same thing right?
int * const start
int const * start
both means the pointer is constant - (pointer always point to same
address)
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Re: pointer vs reference
so start is a reference = memory address?
content of start is likely to be something like -
0x12349870h
??
>>int const& start
>start is a reference to a constant int (the int doesn't change).Comment
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Re: pointer vs reference
Eric Kaplan wrote:A reference doesn't actually exist. A reference is an alias. The compilerso start is a reference = memory address?
>
content of start is likely to be something like -
0x12349870h
>
??
>>>>>int const& start
>start is a reference to a constant int (the int doesn't change).
is free to do that however it wishes. The compiler may actually use the
original variable, or the address, or some other method. You shouldn't
count on how the compiler does it as it may change from compiler to compiler
and even from compiler version to version.
--
Jim Langston
tazmaster@rocke tmail.com
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Re: pointer vs reference
Eric Kaplan wrote:No. Those are not the same.I suppose the following is exact same thing right?
>
int * const start
int const * start
>
both means the pointer is constant - (pointer always point to same
address)
const int* start;
int const* start;
are exactly the same.
int* const start;
start is a constant *pointer* to an int. You can not reseat the poniter.
You can not change where the pointer is pointing to. In fact you better
initialize it since you can't change it. But you can change the integer
that the pointer points to.
int const * start;
start is a pointer to a constant *integer* You can not change the value of
what the pointer points to, but you are free to make the pointer point to
some other memory location.
--
Jim Langston
tazmaster@rocke tmail.com
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Re: pointer vs reference
On 2008-04-04 20:20:30 -0400, "Jim Langston" <tazmaster@rock etmail.comsaid:
The value of the int can change, but you can't change it through 'start'.>>>const int * start
start is a pointer to an int that is constant (the int doesn't change).
>
>>>int const& start
start is a reference to a constant int (the int doesn't change).
>
int i = 0;
const int *start = &i;
std::cout << *start << '\n'; // 0
++i; // OK
std::cout << *start << '\n'; // 1
++*start; // illegal
--
Pete
Roundhouse Consulting, Ltd. (www.versatilecoding.com) Author of "The
Standard C++ Library Extensions: a Tutorial and Reference
(www.petebecker.com/tr1book)
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