para

Pointers are absolutely essential. Start using them whenever you can and become familiar with their uses; trust me, you'll thank yourself years down the road.

A good practice problem is to make a function that takes a string and parses it into an array of tokens. For example:
would return
After you finished, if you used strcpy() anywhere, rewrite the function with the only allocations being for the size of the array, and the size of the initial string (hint: each index is a pointer to somewhere in a copy of the string you save).

I feel this problem is fairly good at teaching you practical uses for pointers, and a string parser is something you may see in the field.

LOI Kratong

DaWei: unfortunately i don't recall ever using a malloc, with or without a pointer, so there you go

para: i'll have a look at what you mean, thanks...

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DaWei

Perhaps you wouldn't consider it so amusing if you realized that not using the heap, whether through malloc or new, is not a positive, but a negative, commentary on skill.

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LOI Kratong

i am not denying the fact that i do not know as much as you, and i do realise that it is a negative comment on my skill but i am currently researching as to what a malloc is!!

EDIT: I now know what it is, but i do not believe that i have had cause to use it yet...

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nnxion

You'd probably be better of sticking to new than malloc anyway.

It is true you are investigating, which is positive.

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lectricpharaoh

Pointers are one of those concepts that can sometimes take a while to wrap your mind around. However, as others have said, knowledge of how to use them is essential in writing anything but the most trivial programs in an efficient manner. The only downside to pointers is that they have a huge potential to cause damage if they are misused, though in a secure operating system, errant pointers should no longer bring down the entire system, format your hard drive, or do other such catastrophic things as they could do under legacy operating systems like DOS.

This perceived potential for misuse coupled with the fact that learning to use them properly often takes a bit of practice are key reasons that certain languages discourage their use (C# comes to mind) or remove them entirely (Java). However, even this is an illusion. When you pass an object to a function in many of these languages, it does not pass the object itself, but a reference (read: 'pointer') to the object instead. This is because the language designers acknowledge the efficiency in doing so. However, using them in other ways is often clumsy at best. The support in C++ of low-level constructs such as pointers is a big reason that it's such a widely-used language.

I suggest you follow the link in DaWei's sig to the pointers introduction. You might need to read it more than once as you play around with pointers. Don't trust the one on (I think) cprogramming.com; if it's the one I remember, it's full of subtle errors and misinformation.

When you're done, you should be able to write a function to swap two variables, and actually have them be swapped. You should hopefully understand the relationship between a pointer and an array (the two can often be used synonymously), as well as the differences. You should learn how pointer arithmetic is performed, and that it is scaled according to the size of the pointed-at quantity (this is why pointers need a type, such as 'int' or 'char'). You should know why array[7] and 7[array] mean the same thing (hint: remember that addition is commutative).

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LOI Kratong

Thanks guys, i'm definately getting there now, i'm starting to understand, and i will read DaWei's intro...

Cheers!

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nnxion

I think you mean the one at cplusplus.com, but cprogramming.com might also be bad? In addition to DaWei's intro to pointers, Narue also has a nice pointer tutorial on her site.

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LOI Kratong

OK i'll check out Narue's too...

EDIT: can't find it on Narue's site. Can i have a link?

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nnxion

Here.

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