Print Subset

void all_subset(vector<int>& A, vector<int>& subset, int index) 
{ 
    print(subset); 
    for (int i = index; i < A.size(); i++) 
    { 
        subset.push_back(A[i]); 
        all_subset(A, subset, i + 1); 
        subset.pop_back(); 
    } 
    return; 
}