array[n++];

**Krak** · 07-05-2005

Whenever I see something like array[n++], I get a bit confused...because I don't really see it that often. Does that kind of syntax come in handy for anything? It's just a way to compound:

Code:

array[n]=n;
n++;

Right? I see it used a lot in loops too, and it kind of throws me off. I've seen it used in a SetString() function too.

And while I'm at it...I should ask: if you wish to pass an array into a function (which I don't think you can do), you would just pass the address of the first element as a pointer, and the number of elements there are in total as an int, right?

**Micko** · 07-05-2005

No, you're wrong,
array[n++] is just short way of writting... You need to have real code to understand what it really means. Yes it is often used in loops. For example

Code:

int n =0;
int array[10];
// some code
while (cin >> array[n++]);
n--;
cout << "You enetered "<<n<< " int numbers."<<endl;

or you can just write

Code:

while (cin >> array[n])
{
n++;
}
// in this case you don't need line n--

Arrays are passed to functions only by reference i.e. through pointer to the first element...
When you passed arrays as function arguments usually you need to provide information about array length as well (except for C-style string, where you can determine length with '\0')

- Micko

**Jaken Veina** · 07-05-2005

Originally Posted by Micko

No, you're wrong

Umm.....how? There's nothing wrong with what he said at all. And your post....you just reiterated what he said, especially with the part about passing arrays.

**JoshR** · 07-05-2005

Ya thats correct

Code:

array[n++] = number;

// is the same as...

array[n] = number;
n++;

**Daved** · 07-05-2005

This part of what Krak said was wrong:

array[n++]

is not the same as

array[n] = n;
n++;

The first bit of code can be used in many different situations, and most if not all of them are different than the second piece of code.

**quzah** · 07-05-2005

Specifically, this is what was wrong with the statement:

Code:

array[n++]

This by itself does nothing at all other than increment the variable n. What you meant to say I believe was something like this:

Code:

array[n++] = foo;

The above is identical to this:

Code:

array[ n ] = foo;
n++;

To further the point, this means:

Code:

array[n++]

"at array element n, do whatever, then increment n"

Quzah.

**dwks** · 07-05-2005

However,

Code:

//prefix
array[++n] = var;

is different from

Code:

//postfix
array[n++] = var;

The first one (pretfix) increments n, and then assigns var the value or array[n]. In other words, it's like

Code:

n++;
array[n] = var;

The other sample, postfix, is like this code:

Code:

array[n] = var;
n ++;

**Krak** · 07-06-2005

I knew that.

I don't really think there's any real reason to compound the two statements like that. I think it really takes readability away from code sometimes.

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