16. Closest Numbers C++

#include <iostream>
#include <vector>
int main()
{
    using namespace std;

    int lenght, n;
    cin >> lenght;
    vector<int> arr;
    for (int i = 0; i < lenght; ++i)
    {
        cin >> n;
        arr.push_back(n);
    }

    int min_diff = 0;
    if (lenght > 1)
    {
        min_diff = abs(arr[0] - arr[1]);
        for (int i = 0; i < lenght; ++i)
            for (int j = i + 1; j < lenght; ++j)
                if (abs(arr[i] - arr[j]) < min_diff)
                    min_diff = abs(arr[i] - arr[j]);

    }

    cout << min_diff;

    return 0;
}