how to generate sub-arrays from an array?

int a[] = {1, 2, 3, 4, 5};
int n = sizeof(a) / sizeof(int);
for (int i = 0; i < n; i++) {
  for (int j = i + 1; j < n; j++) {
    cout << "{" << a[i] << "," << a[j] << "}";
  }
}