1. DeMorgan's & related Laws

2. Given a Conditional Expression,
When its NOT true
Given a Conditional Expression,
apply the NOT operator
!(cond)

3. How are these laws useful?
if (cond) // do this when cond is true else // do this when !cond is true

4. if (cond) { } else // !cond
Useful else comment
if (cond) { } else // !cond

5. Useful else comment
if (a < 0) cout << "negative"; else // a >= 0 cout << "zero or positive";

6. < >= > <= == !=
Relational Operators
Operator
"Not of" the Operator
<
>=
>
<= == !=

7. || && ! Logical Operators Operator "Not of" the Operator
! ! cond is cond

8. if ((a <= 3) ||(b != 0)) { } else { // ((a > 3) && (b == 0))
Example 1
if ((a <= 3) ||(b != 0)) { } else { // ((a > 3) && (b == 0))

9. if ((a > 3) &&(b == 0)) { } else { // ((a <= 3) || (b != 0))
Example 2
if ((a > 3) &&(b == 0)) { } else { // ((a <= 3) || (b != 0))

10. Example 3
if ((a >=0) && (a<=9)) cout << "single digit number"; else // (a < 0) || (a > 9) cout << "notsingle digit num";

11. if (!(a > 3)) { } else { // (a > 3) is !!(a>3)
Example 4
if (!(a > 3)) { } else { // (a > 3) is !!(a>3)