printf "%.17e\n", 1.00000000000000040e+000;;
1.00000000000000040e+000

printf "%.17e\n", 5.00000000000100030e-016;;
5.00000000000100030e-016

##</code><code>##

printf "%.17e\n", $S = 1.00000000000000040e+000 + 5.00000000000100030e-016;;
1.00000000000000090e+000

##</code><code>##

printf "%.17e\n", $S = 1.00000000000000040e+000 + 5.00000000000100030e-016;;
1.00000000000000090e+000

printf "%.17e\n", $e = ( $S = 1.00000000000000040e+000 + 5.00000000000100030e-016 ) - 1.00000000000000040e+000;;
4.44089209850062620e-016

printf "%.17e\n", ( $e = ( $S = 1.00000000000000040e+000 + 5.00000000000100030e-016 ) - 1.00000000000000040e+000 ) - 5.00000000000100030e-016;;
-5.59107901500374110e-017