Question on associative arrays

SystemVerilog
,
1

I have the following code. I was trying to create a unique 3x3x3 matrix with unique elements. After randomization I am storing them into an associative array and later printing the elements of the associative array. I was expecting the size of associative array is 27. But I am seeing the size as 32.

Could some one explain this behavior of associative array?

class matrix;
 
  rand int a [3][3][3];
  rand int b [3][3][3];
  int A[int] = '{default:0};
 
  constraint c1 {
    foreach(b[i,j,k])
      b[i][j][k] inside {[1:35]};
    unique{b};
  }

  function void post_randomize();
    $display("%p", a);
    foreach(b[i,j,k]) begin
      $display("%d", b[i][j][k]);
      A[b[i][j][k]]=1;
    end
    foreach(A[i])
      $display("A[%d]=  %d", i, A[i]);
    
    $display("A.size:%d", A.size);
  endfunction

endclass

module tb;
  
  matrix C;

  initial begin
      C = new;
    repeat(5)
      C.randomize();
    
  end
  
endmodule
2

The size of A is 27 after the first time you call randomize. You would need to call A.delete() to erase the previous contents of the array.