What means "!" mean in pseudo code? I know "!" means factorial, but I can’t translate it

Question

What does it mean ! in pseudo code? I know that ! denotes factorial, but I cannot translate it.

eg:

get surgery

 if (operation!= B OR operation != D OR operation!= W) then print "Invalid Operation" 

What does it mean?

Answer 1

It means no. So your sample code

 if (operation!= 'B' OR operation != 'D' OR operation!= 'W') 

can read like

"If the operation is not equal to" B "or the operation is not equal to" D "or the operation is not equal to" W ""

Answer 2

!= means not equal, but ! usually does not mean negation.

Answer 3

In general

! not
|| means logical or
&& means logical and

Example:

 !false == true ( == means equality )