Why is the out-printed string displaying the wrong values?

The code of the fprintf-part:

coordPoints = [convexHull,coordsConvex].';
fprintf('convex hull points:');
fprintf(' %d (%d %d),',coordPoints(:,1:end - 1))
fprintf(' and %d (%d %d).\n',coordPoints(:,end))

The current output:

convex hull points: 16 (0 3), 13 (0 0), 11 (6 0), 8 (8 0), 5 (8 6), 1 (0 8), and 18 (0 4).

The desired output:

convex hull points: 16 (-10 3), 13 (-9 -5), 11 (6 -10), 8 (8 -7), 5 (8 6), 1 (-7 8), and 18 (-10 4).

It is clearly caused by the negative values, but I can't seem to figure out how exactly.

The variable coordsConvex

-10	  3
 -9	 -5
  6	-10
  8	 -7
  8	  6
 -7	  8
-10	  4

The variale coordPoints

16	13	11	8	5
 0	 0	 6	8	8
 3	 0	 0	0	6

[Adam Danz]

The only inputs to your fprintf() commands are values from coordPoints but your desired output includes values that aren't from that set such as -10, -9, all of the negative values....

[The Merchant]

When my list is

coordsInput = [  % Points
3 12    % 1
10 8    % 2
11 14   % 3
13 16   % 4
9 19    % 5
1 15    % 6
2 6     % 7
6 1     % 8
12 5    % 9
16 7    % 10
14 17   % 11
19 18   % 12
];

it does work, also with both on coordsInput.

Its very weird.

I think it goes wrong when coordsPoint is established, but I dont know why

[Adam Danz]

@ The Merchant, the majority of help this forum provides is by users searching for pre-existing questions and finding answers. Lots of volunteers have invested their time into answering questsions and when the content of those questions is removed, the investment of that time turns out to be a waste. It's disrespectful to ask for help and then eliminate the utility of the time they gave you.

[Rena Berman]

(Answers Dev) Restored edit

[Adam Danz]

Thanks, Rena!

Answer 1

[Adam Danz]

convexHull is a 32-bit unsigned integer array.

This line below changes the values of convexHull.

coordPoints = [convexHull,coordsConvex].'; 

To prevent that, convert to double

coordPoints = [double(convexHull),coordsConvex].';
%              ^^^^^^^
fprintf('convex hull points:');
fprintf(' %d (%d %d),',coordPoints(:,1:end - 1))
fprintf(' and %d (%d %d).\n',coordPoints(:,end))

Result

convex hull points: 16 (-10 3), 13 (-9 -5), 11 (6 -10), 8 (8 -7), 5 (8 6), 1 (-7 8), and 18 (-10 4).

[The Merchant]

thanks!

[Adam Danz]

Glad we finally got there. ;) That answer would have been impossible without the code which came after a bit of dialog.