Java 6 Illuminated: An Active Learning Approach, 2nd Edition

216 CHAPTER 5 Flow of Control,Part 1: Selection

TABLE 5.7 Truth Table for DeMorgan’s Laws

a b !a !b a && b a || b !(a && b) !a || !b !(a || b) !a && !b

true true false false true true false false false false

true false false true false true true true false false

false true true false false true true true false false

false false true true false false true true true true

TABLE 5.8 The Logical NOT Operator Applied to Relational and Equality Operators

Expression ! ( Expression )

a == b a != b

a != b a == b

a < b a >= b

a >= b a < b

a > b a <= b

a <= b a > b

In Java, therefore, using the first law, we see that

!( a && b ) is equivalent to !a || !b

Using the second ...