sounds like you are a beginner? is it a string array? if you are just using numbers, you should use a number data type for the array.

Let me make sure I understand the question:

You have an array of a certain size. You want to remove any zero entries, shrinking the size of the array?

at fiedler, yes i am a beginner.

for abge. I dont want to shrink the size of the array, just be able to move the cells with actual data to the front but keep the array size the same. so after i call the method, i could enter another instance of data to cell 7 for example

use a queue rather than an array?

The specifics would vary from language to language, but arrays are typically fixed in size, unlike collections (i.e. lists). Create a new array with the same size. Loop through the array and increment a counter every time you find a non-zero value and assign that value to the counter position in the new array. I'm assuming you are in VB here, so redim preserve the new array to the counter size. You now have a scaled down version of your array without any zero values.

Well, I just saw what you really want done and it just got easier.

Initialize a counter to 1 (or 0 depending on the language).

Check the array value at counter.
If it is non-zero loop through the array incrementing the counter until you find a zero value. This will get your first zero value.

Loop through the array starting at counter+1.
Every time you find a non-zero value, swap it with the zero in the counter position and increment the counter until you find a zero value.

This will result in pushing all the values to the front (or back if youy work backwards and decrement instead of increment).

Just remember to include checks in you counter loops so you don't exceed the end of the array.

You can just use a recursive loop to drain the values to the front of the array, if that is what you need.

drain(array)
{
for(each)
{

OK, here's the pseudo-code:

do i from 1 to size of array
if(a(i)==0)
do from j=i+1 to size of array
if(a(j)=/=0)
temp=a(i)
a(i)=a(j)
a(j)=temp
exit loop
endloop

Goodness if I'd known it was homework help night I could have had some interesting problems . . . =)

argh, so much for tabs, but you get the idea.

What language is that, stumerac?

stupid forums are weird for my computer. I lose control of the keyboard sometimes.

drain(array[point])
{
for(each)
{
if ( array[i] does not equal 0 AND i does not equal maxArraySize )
drain(i +1)
else
i = i + 1
}
}

Or something like that. I bow to real programmers.

Late night half-inebriated language.

I hate recursive code. It's probably from that one time I had to code recursively in Assembly for an exam. Never got that bad taste out of my mouth.

That question still doesn't make any sense to me.

Eeeeeew! A recursive function. Blech!

Keeping the parallel counter is more efficient because you don't have to run an internal loop from I+1.

int curPos = 0;
for (int i=0; i < array.length; i++) {
if (array[i] != 0) {
while (curPos < array.length && array[curPos] != 0) {curPos++;}
array[curPos]=array[i];
}
}

Oops, I forgot to reset the value at i.

Right after:
array[curPos]=array[i];

add:
array[i]=0;

Found another bug, so here is the corrected version.

int curPos = 0;
for (int i=0; i < array.length; i++) {
if (array[i] != 0) {
while (curPos < array.length && array[curPos] != 0) {curPos++;}
if (curPos < i) {
array[curPos]=array[i];
array[i]=0;
}
}
}

Recursion sure is pretty, but it is destructive to memory and only deserves to be in academia, not real life ;)

What problem are you solving that your array starts off with values in random places, and you need to shrink it? Are you hashing the values, then need to get the values? I've got a pretty OO way of doing this if you are against queues.

fortknox +1

That's why I said "Eeeeeew!" to his needless recursion. It has it's place, but not as a substitute for a simple "for next", "for each" or "do while" loop. If you need to traverse through containers and you don't know what depth they are at, recursion is the way to go, but not here.

Also, if you list what the purpose of the process is overall, we might be able to build a better solution for you.

Here's java code I just whipped up (no good error checking, and very basic for the newbie), but since it isn't going to format right, I'll put it somewhere you can download it:
http://dl.dropbox.com/u/6076492/ArrayFun.java

The output looks like this:
--Start array
Array values: [0, 0, 3, 0, 0, 0, 7, 0, ]
--New array, initialized
Array values: [0, 0, 0, 0, 0, 0, 0, 0, ]
--New array, drained
Array values: [3, 7, 0, 0, 0, 0, 0, 0, ]

That code, obviously, just does what you ask, but if I knew WHAT you were doing, I could give you a much more elegant solution (because it sounds like what you are doing shouldn't involve arrays).

But fortknox, you missed one of the requirements. He said " so after i call the method, i could enter another instance of data to cell 7 for example" which means it needs to be the same array or reload the array from your new one. My C# code does just that by just reorganizing and processing one array. I'll take a few moments and transfer it into a command line program in VS with the instantiation code and post the results here.

What's wrong with reassigning the pointer?
array = newArray;

I was just trying to simplify it as much as possible for the newbie so it wasn't hard to read. You are basically writing almost a sorting algorithm, which he should start to understand, but may be a bit beyond him (just an assumption on my part)

OK, back from my meeting. Let me sit down and throw together a working C# example of my algorithm.

Start
array [ 0, 0, 3, 0, 0, 0, 7, 0]

Drained
array [ 3, 7, 0, 0, 0, 0, 0, 0]

I'll find some place to post the code up and post the link here.

www.draugnar.com/Program.cs