NOT _ _ _ _ _ _ _ _ _ _ _ _ operator

The not operator returns true if its argument evaluates to nil, and nil if its argument is true .

syntax:

not(<logical expression>)

examples:

if not numberp(a) then write "indeterminate" else write a;
			 


  indeterminate; 


a := 10; 

  A := 10 


if not numberp(a) then write "indeterminate" else write a;
			 


  10 


if not(numberp(a) and a < 0) then write "positive number";
			 


  positive number

Logical operators can only be used in conditional statements such as

if...then...else or while...do.