Enable and Disable Delayed Expansion, what does it do?

Question

I\'ve seen SETLOCAL ENABLEDELAYEDEXPANSION & SETLOCAL DISABLEDELAYEDEXPANSION in many batch files but what do the commands actually do?

Answer 1

ALSO note that with SETLOCAL ENABLEDELAYEDEXPANSION you cant echo !!!!!! so:

echo my sentence! 123

will be outputed as:

my sentence 123