Identifiers are names used for line labels and symbols.
An identifier may be any sequence of letters ,digits,and
underscores,but it must not start with a digit.
Identifiers may be any number of characters in length :
however,the compiler will recognize only first 32
characters .Identifiers are not case sensitive hence
the labels LOOP:loop:Loop,etc will be read equivalently.
Labels are anchor points in our program.They are identifiers
followed by a colon.
Symbols make our program more readable.They use identifiers
to represent the constants,variables or other quantities.
Symbols cannot be used for line labels
symbol five = 5 'symbolic constant
symbol number = W2 'named word variable