Selection Sort
Selection Sort is an elementary sorting algorithm that is designed to minimize 
the number of exchanges that are performed. 
It works by making N-1 passes over the unsorted portion of the array, each time 
selecting the largest value. This value is then moved into its final sorted 
position with a single exchange. 
Here is a procedure that implements Selection Sort, assuming a global array a[ ] 
with n elements, and a procedure called swap( ). 

    

procedure selection_sort;
  var
    i		: integer;
    top		: integer;
    max		: integer;
  begin
    for top := n downto 2 do
      begin
        max := top;
        for i := 1 to top-1 do
          if a[i] > a[max] then
            max := i;
        swap(a[top],a[max])
      end
  end;

    
    DOWNLOAD selection.pas (complete program) 
Selection Sort requires about N2/2 comparisons and about N exchanges, and is 
quite insensitive to the original ordering of the input data.