Some exercises which we may discuss in lecture first: 

1. What does this code do: --------------------------------------------------

if False and False or True: 
  print False
else:
  print True 

2. What does this code do: --------------------------------------------------

if False and (False or True): 
  print False
else:
  print True 

3. How can you simplify: ----------------------------------------------------

(x < 5) and (x < 25)

Assume x holds a number. 

4. Likewise, how would you simplify each one of these: ----------------------

a) (x < 5) or (x < 25)
b) (x > 3) or (x < 5)
c) (x > 3) and (x < 5)

5. Consider the following two program fragments. Assume that x is an int variable.

    // fragment 1    |         // fragment 2
                     |
    if x == 5:       |         if x == 5:
       x = x + 1     |            x = x + 1
    else:            |         if x != 5:
       x = 8         |            x = 8

Which of these statements is true?

  a) The two fragments are logically equivalent.
  b) If x is 6 initially, then
       -- the value in x is 8 after executing fragment 1 and
       -- the value in x is 6 after executing fragment 2. 
  c) Fragment 2 contains a syntax error.
  d) x always has the value 8 after executing fragment 2.
  e) x has either the value 5 or the value 8 after executing fragment 1. 

6. Also, please simplify the following two statements: 

  a) !(((x > 0) or (x == 0)) and (x < 10))

  Warning: Don't overlook the logical negation (bang!) at the front.

  b) !(((x > 0) or (x == 0)) or (x < 10))

  Warning: same as before. 

In both cases assume x is an integer. Does anything change if x is a float? 

Also I am going to post the code we develop in class below: 

for something in range(10): 
  print "*", 

This code prints 10 stars, on the same line. 

for whatever in range(10):
  for something in range(10): 
    print "*", 
  print

This code prints a 10 by 10 square of stars. 

size = int(raw_input("Please enter the size: "))

for line in range(size): 
  for column in range(size): 
    if line + column == size - 1 or line == 0 or line == size-1 or line == size/2 and size/3 <= column <= 2 * size / 3:
      print "*", 
    else: 
      print " ", 
  print

This code prints the scalable Z we talked about. 

In class we also developed a scalable 4: 

size = int(raw_input("Please enter the size: "))
       
for line in range(size):
  for column in range(size):
    if line + column == size / 2 or \
       line == size / 2 and column <= 3 * size / 4 or \
       column == size / 2 and line >= size / 4:
        print "*",
    else:
      print " ",
  print

I'm going to add this to the study guide tonight.