Reverse array

[goldyn]

How can I get my array to output it's reverse with what I've already created? I'm confused.

 #include <iostream>
#include <stdlib.h>
using namespace std;

const int MAX_INTEGERS = 20; //Max numbers in array always constant

void fill_array(int a[], int size, int& number);



int main()
{
	if (system("CLS")) system("clear"); //clears garbage from screen

	int integers[MAX_INTEGERS], number;

	cout << "This program outputs an array backwards" << endl;

	fill_array(integers, MAX_INTEGERS, number);

	return 0;
}

void fill_array(int a[], int size, int& number)
{
	cout << "Enter up to " << size << " integers.\n"
		<< "Mark the end of the list with a 0.\n";
	int next, index = 0;
	cin >> next;
	while ((next >= 1) && (index < size)) //prompts user for integers until 0 is input
	{
		a[index] = next;
		index++;
		cin >> next;
	}

	number = index;

	cout << "The reverse order of the array is" << endl;
	//
	//
	//Confused on the code here
	

}

[giblit]

If you are just trying to output the reverse then you can start from the last element and work towards the first.
for(int i = size-1; i > -1; --i)


By the way, shouldn't line 30 be

while(next && index < size)

//or

while(next != 0 && index < size)

What about negative numbers?

[Jacobhaha]

My example was wrong, just ignore my post here.

[disturbedfuel15]

For your reference, just answered yesterday.

http://www.cplusplus.com/forum/beginner/147276/

[liuyang]

You can simply reverse the array with the following idea:

1. Swap first item with last item
2. Swap second item with the item before last item
3. Go on until you hit the middle of the array

[goldyn]

wow that was so simple and I was making it much more of a problem... Thanks, and yea I just noticed line 30, thanks. Just trying to figure stuff out ahead of time for class and learn stuff on my own before I get assigned something difficult. Thought I'd mess with arrays for a while and self teach : )
Thanks

[giblit]

@Jacobhaha

int hello = a[index - 1];
	while(hello >= 0)
	{
	    cout << hello-- << ", ";
	}

this does not reverse an array unless they are in ascending order and have a difference of one. You are just creating a variable, assigning it a value of the last element, hoping the value of it is > 0 and then hoping that each consecutive item is one less in value.

Maybe you are thinking hello is a pointer?

[Jacobhaha]

@giblit
you are right, now i see it haha. For some reason i just assumed the array was: 1, 2, 3 up to 20 and ended with 0.