Haw can we use and or not statement perfectly

Answer 1

Or is ||
And is &&
not is !
and and or need 2 or more than two operands while not needs just one

if(a||b) {}
the statements are evaluated if either a or b are true. Similarly &&.
if(!a) {}
it is evaluated if a is false

Answer 2

My habit is name it in purpose and literally.

for example:
bool both_a_and_b_is_true= a&&b ;

if( both_a_and_b_is_true)
do something

else
do something