Truth Tables and De Morgan's Rules
Read this chapter, which discusses Boolean variables as used in decision tables. Truth tables are used to collect variables and their values relative to decisions that have to be made within control structures.
17. Full Price Hotel
Answer:
Using the De Morgan Rule
!(A && B)
is equivalent to!A || !B
the expression
boolean shipping = !(purchase >= 50 && !onSale );is equivalent to
boolean shipping = !(purchase >= 50) || !!onSale ;which can be further transformed to
boolean shipping = purchase < 50 || onSale ;
Full Price Hotel
A hotel charges full price for its rooms during the "on season" when a reservation is made less than 14 days in advance. Otherwise, a reservation qualifies for a discount.
boolean fullFare = (days < 14) && onSeason;
Assume that onSeason
is a boolean variable. Here is an expression that says when a discount rate may be available:
boolean discount = !( (days < 14) && onSeason );
Question 17:
Rewrite this expression in two steps. In the first step, apply De Morgan's rule that
!(A && B)
is equivalent to!A || !B
.In the second step, rewrite the relational expression:
boolean discount =
boolean discount =