# Sorting an array— issue

I'm asking for help with a problem implying an array sorting in the following manner: all even numbers must be in front of the odd ones. I've partially made the problem, but I did the sorting in the opposite manner and I can not manage to fix it.

``````#include "stdafx.h"
#include <iostream>
using namespace std;

int main()
{
int v[100], n, i, aux = 0, inv;
cout << "Number of elements: ";
cin >> n;
for (i = 0; i < n; i++)
{
cout << "v[" << i << "]=";
cin >> v[i];
}

do
{
inv = 0;
for (i = 0; i < n; i++)
{
if (v[i] % 2 == 1 && v[i + 1] % 2 == 0)
{
inv = 1;
aux = v[i];
v[i] = v[i + 1];
v[i + 1] = aux;
}
}
} while (inv != 0);
cout << endl;

for (i = 0; i < n; i++)
cout << v[i] << " ";
cout << endl;
system("pause");
return 0;
}
``````

The output for this would be:

``````n = 8
1 3 2 4 7 8 4 2

Result: 2 4 8 4 2 -858993460 1 3
``````

In the expression `v[i + 1]`, you access `v[n]` when `i = n - 1`, this will result in an out-of-bounds memory access which results in undefined behaviour. You should change the `for` loop to this:

``````for (i = 0; i < n - 1; i++)
``````

The output for the given input is:

``````a.exe
Number of elements: 8
v[0]=1
v[1]=3
v[2]=2
v[3]=4
v[4]=7
v[5]=8
v[6]=4
v[7]=2

2 4 8 4 2 1 3 7
``````