How do I sort an array in descending order without using the sort function?

A =  [2 1 4 3 6 5 8 7 10 9 12 11 14 13 16 15 18 17 20 19]

Answer 1

[Thorsten]

You can use bubble sort:

swapped = 1; 
while swapped
  swapped = 0; 
  for i=1:numel(A)-1
    if A(i+1) > A(i)
      temp = A(i); A(i) = A(i+1); A(i+1) = temp; swapped = 1; 
    end
  end
end

Answer 2

[Walter Roberson]

flipud(unique(A(:)))

Answer 3

[Stephen23]

Here are a few ways to sort an array of unique values without using sort:

sortrows(A(:),-1)

A(end:-1:1) = unique(A);

fliplr(union(A,A(1)))

fliplr(setdiff(A,NaN))