for i:=1 to n - 1 do
   begin
     k:=0;
     x:=a[i];
     for j:=i+1 to n do
     if (a[j] < x) then
       begin
         k:=j;
         x:=a[j];
       end;
     if (k > 0) then
       begin
         x:=a[i];
         a[i]:=a[k];
         a[k]:=x;
       end;
   end;