Homework # 6 - due Tuesday October 4th

Read the section on pre and post conditions and do problems 19 a and b and 20 a from Chapter 3 found on pages 172 & 173 (also shown below)

19. Compute the weakest precondition for each of the following statements and postconditions

a. a = 2 * (b – 1) – 1 {a > 0}

b. b = (c + 10) / 3 { b > 6}

20. Compute the weakest precondition for each of the following sequences of assignment statements and their postconditions

a. a = 2 * b + 1;

b = a – 3

{ b < 0}