how i can improve my programming skill in pointer using c++
-
-
Re: to improve programming in pointers
by more reading and practices.
Ben
-
Re: to improve programming in pointers
sivashankar21@g mail.com wrote:[color=blue]
> how i can improve my programming skill in pointer using c++
>[/color]
Go find the answers to these questions.
struct A { int a; };
struct B : A { int b; };
A xa[ 10 ];
B xb[ 10 ];
A * pa = xb;
// Q1 - what is the value of pa pointing to ?
A * pBAD = pa + 1;
// Q2 - why is pBAD, bad ?
B * pb = xb;
// - same as Q1
A * paOK = pb + 1;
// Q3 - what does paOK point to ?
A (&( * pf )( int * ))[ 10 ];
// Q4 - what is pf ?
A * paX = & pb[1];
bool b( paX == paOK );
// Q5 - what is the value of b
A * paY = & pb[3];
int iNOTGOOD( paY - paX );
// Q6 - Why is iNOTGOOD not good ?
A * paM = new B;
int main()
{
delete paM; // line Z - NOT GOOD
// Q7 - why is line Z a bad thing ?
paM = 0;
// Q8 - what is paM now ?
delete paM;
// Q9 - what does delete paM do ?
bool x( & (* xb).b == & xb->b );
// Q10 - What is the value of x ?
}
B * F()
{
B x[2];
return x; // doh !
// Q11 - Why is the line marked "doh" broken ?
}
Comment
-
Re: to improve programming in pointers
sivashankar21@g mail.com a écrit :[color=blue]
> how i can improve my programming skill in pointer using c++
>[/color]
You shouldn't even use pointers.
Avoid them as much as possible and only use them when it's needed.
Comment
-
Re: to improve programming in pointers
loufoque wrote:
[color=blue]
> sivashankar21@g mail.com a écrit :[color=green]
> > how i can improve my programming skill in pointer using c++
> >[/color]
>
> You shouldn't even use pointers.
> Avoid them as much as possible and only use them when it's needed.[/color]
At which point he won't know how to use them.
Brian
--
If televison's a babysitter, the Internet is a drunk librarian who
won't shut up.
-- Dorothy Gambrell (http://catandgirl.com)
Comment
-
Re: to improve programming in pointers
Default User wrote:[color=blue]
> loufoque wrote:
>
>[color=green]
>>sivashankar21 @gmail.com a écrit :
>>[color=darkred]
>>>how i can improve my programming skill in pointer using c++
>>>[/color]
>>
>>You shouldn't even use pointers.
>>Avoid them as much as possible and only use them when it's needed.[/color]
>
>
> At which point he won't know how to use them.
>[/color]
But he may have developed sufficient skill in in avoiding them so he
doesn't have to!
Are there any (real world) instances where pointers can't be avoided?
--
Ian Collins.
Comment
-
Re: to improve programming in pointers
Ian Collins wrote:
....[color=blue]
>
> Are there any (real world) instances where pointers can't be avoided?[/color]
Let's see:
a) the "this" keyword.
b) When you may or may not want to pass an interface ... e.g.
void DoThing( const A & a, ErrorReporter * e = 0 );
c) Intrusive reference counted objects.
d) When objects point to one another i.e. a<->b
+ many more
Comment
-
Re: to improve programming in pointers
Gianni Mariani wrote:[color=blue]
> Ian Collins wrote:
> ....
>[color=green]
>>
>> Are there any (real world) instances where pointers can't be avoided?[/color]
>
>
> Let's see:
>
> a) the "this" keyword.
>
> b) When you may or may not want to pass an interface ... e.g.
>
> void DoThing( const A & a, ErrorReporter * e = 0 );
>
> c) Intrusive reference counted objects.
>
> d) When objects point to one another i.e. a<->b
>
> + many more[/color]
With the exception of a, all these can be replace by some form of smart
pointer object.
--
Ian Collins.
Comment
-
Re: to improve programming in pointers
Ian Collins wrote:
....[color=blue]
>
> With the exception of a, all these can be replace by some form of smart
> pointer object.[/color]
You still need to understand pointers even if you're managing them using
smart pointers.
Comment
-
Re: to improve programming in pointers
Gianni Mariani wrote:[color=blue]
> Ian Collins wrote:
> ....
>[color=green]
>>
>> With the exception of a, all these can be replace by some form of
>> smart pointer object.[/color]
>
>
> You still need to understand pointers even if you're managing them using
> smart pointers.
>[/color]
True enough, but I was trying to think of an example where raw pointers
can't be replaced with smart pointers.
--
Ian Collins.
Comment
-
Re: to improve programming in pointers
> True enough, but I was trying to think of an example where raw pointers[color=blue]
> can't be replaced with smart pointers.
>[/color]
When you are writing your own smart pointers? Perhaps?
Ben
Comment
Comment