[ethaninja]

Can anybody explain to me what pointers do in layman terms? I'm on this tutorial but he sort of Wikipedialized it so it is very hard to read without stressing for a brain aneurysm.
So if anybody knows how to dumb it done for those that are a little slower on the learning curves I would greatly appreciate it  

[Scooby_Doo]

A pointer just points to someplace in memory.  Instead of storing the actual data it just tells you where it's located, useful for strings and dynamic stuff.

[Mongoose]

What Scooby_Doo said.  A pointer is the address of a specific location in memory; you can use it to put a piece of data there and then find it later.  The actual value of a pointer is just an address value, not the data itself.  There's a related term called "dereferencing," which basically means retrieving the data that a pointer is pointing to.

[ethaninja]

What Scooby_Doo said.  A pointer is the address of a specific location in memory; you can use it to put a piece of data there and then find it later.  The actual value of a pointer is just an address value, not the data itself.  There's a related term called "dereferencing," which basically means retrieving the data that a pointer is pointing to.

Ah ok. So it's not actual data, but a location of where to find it sort of thing?

[Scooby_Doo]

Correct.

Very rough example:

Code: [Select]

int value  = 1 ;
int *pointerValue = &value ; // pointerValue now contains the address of where value is stored at.

print pointerValue ; // some goobly gook value
print *pointerValue ; // 1

value = 2 ;
print *pointerValue ; // 2 

*pointerValue = 3 ;  // Note i'm dereferencing the pointer (i.e. i'm assigning 3 to into the memory address pointerValue is keeping)
print value ; // 3


[Spicious]

Watch the video: http://www.youtube.com/watch?v=i49_SNt4yfk&feature=related

[sigtau]

Holy crap, Scooby Doo, you just cleared up the one thing in C++ that I didn't ever, ever, EVER understand.

[ethaninja]

Watch the video: http://www.youtube.com/watch?v=i49_SNt4yfk&feature=related

Haha that video is SWEET. Wish all tutorials were like that
Cheers for the reference

[Bobboau]

another way to think of pointers is as variable variables.

[Scooby_Doo]

Also pointers are far faster to send as parameters for a function.  Instead of copying all the data to the function call stack it just copies the pointer's value ( just a memory address). 

Also use references when possible, they're safer than pointers.

[Qent]

You don't have to do anything special for that though. Big things like arrays get passed to functions as a reference automatically. ints don't need to be because they're the same size as pointers.

[Spicious]

It seems a bit limiting to never use classes.

[Topgun]

Pointers are necessary if you want a function to manipulate data of another function.

[Bobboau]

It seems a bit limiting to never use classes.

why would you never use classes?

[Scooby_Doo]

You don't have to do anything special for that though. Big things like arrays get passed to functions as a reference automatically. ints don't need to be because they're the same size as pointers.

When did this change? 

int MyHugeArray[MAXINT] ;

somefunction (MyHugeArray) ; // makes a copy of MyHugeArray

[Spicious]

why would you never use classes?

The post above implied only using things that are small enough to pass by value or arrays which pass by reference implictly.

When did this change? 

int MyHugeArray[MAXINT] ;

somefunction (MyHugeArray) ; // makes a copy of MyHugeArray

Never?
Arrays usually act like pointers.

[Sushi]

You don't have to do anything special for that though. Big things like arrays get passed to functions as a reference automatically. ints don't need to be because they're the same size as pointers.

When did this change? 

int MyHugeArray[MAXINT] ;

somefunction (MyHugeArray) ; // makes a copy of MyHugeArray

My understanding was that since arrays are pointers in c/c++, this is passing just the address of the start of the array, so this is effectively passing the array by reference. If, however, the array was wrapped in a class or struct, the whole thing would get copied.

[Mongoose]

Yeah, I know that passing an array into a function passes its address, so that the function manipulates the original array.  You'd have to explicitly make a copy of the array if you didn't want the original to be changed.

[ethaninja]

why would you never use classes?

The post above implied only using things that are small enough to pass by value or arrays which pass by reference implictly.

When did this change? 

int MyHugeArray[MAXINT] ;

somefunction (MyHugeArray) ; // makes a copy of MyHugeArray

I thought Arrays were used if you wanted to clone something?
Never?
Arrays usually act like pointers.

[portej05]

Also use references when possible, they're safer than pointers.

This isn't entirely valid. If you're using smart pointers, you may be passing the smart pointer class, but the pointer is actually NULL!
(I know, minor, subtle point, but it's caught people before - not only that, sometimes a pointer makes more sense!)