Solution to Practice Problem Set 1
----------------------------------
1(a) 
0
1
1
0
1
0
1

1(b)
1
0
1
1
0
0
0
1

1(c)
Nothing

1(d)
Nothing. With n being equal to -50, the program never enters the 
while-loop.

1(e)
We get the following error message:

Traceback (most recent call last):
  File "None", line 1, in <module>
ValueError: invalid literal for int() with base 10: 'hello'

The error is caused by the fact that the function call to int() expects
an argument that can be translated into a valid integer. The string 'hello'
clearly cannot.

2(a)
9
7
1
3

2(b)
This function outputs the digits of the given non-negative integer in right-to-left
order.

3(a) 
0
4
16
36
64

3(b)
4
16
36
64
100

4(a)
0
2
4
6
8

4(b)
On Wing IDE, the program seems to "hang" forever, until I restart the shell, but
if I use python outside of Wing IDE (this is possible to do) I get output
runs through the infinite sequence of even numbers starting at 0, until I kill
the program. In both cases, the reason for this behavior is that with number equal 
to 9, the while-loop will only terminate when count equals 9 and since count
starts at 0 and increments by 2 in each iteration of the while-loop, it never
reaches 9. 

5(a)
n
20
6
2
0

5(b)
n
10
12
14
16

5(c)
n  m
10 20
11 18
12 16
13 14
14 12

5(d)
10
11
12

6(a)
Run-time error; the variable count is used before it is initialized.

6(b)
Syntax error; the colon at the end of the while-statement is missing.

6(c) 
Semantic error; the program is stuck in an infinite loop because count
is not incremented inside the while-loop.

6(d) 
Semantic error; the output starts with "The square of 2 is 4." It is 
supposed to start with "The square of 1 is 1."

6(e) 
Semantic error; the output looks like
The square of count is 1
The square of count is 4
The square of count is 9
...

Instead of the word "count" actual numbers 1, 2, 3, etc., should
appear in the output.

Correct program
---------------
n = int(raw_input("Enter a number: ")) 
count = 1
while count <= n:
        print "The square of", count, "is", count*count
        count = count + 1