how to find the subsequences of an array

void subsequence(char *in, char *out, int i, int j)
{
    // Base Case
    if (in[i] == '\0')
    {
        out[j] = '\0';
        cout << out << endl;
        return;
    }

    // Recursive Case
    // include the ith character
    out[j] = in[i];
    subsequence(in, out, i + 1, j + 1);
    subsequence(in, out, i + 1, j);
}