Question

What does ! mean in pseudo-code? I know ! stands for factorial but I can’t translate it .

ex:

get operation

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

What does it mean?

Answer 1

It means “not”. So your example code

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

can be read as

“If operation does not equal ‘B’ or operation does not equal ‘D’ or operation does not equal ‘W'”