MONT 105S, Spring 2009

Review sheet for midterm

The following topics have been covered in the first part of the course. Each of the following topics may appear on the exam.

1.  Python programs
	General form of Python program
	Input and Output (print, input() and raw_input())
	Variables
		Rules for naming variables
		Assigning values to variables
	Data types (integer, floating point, string)
	Arithmetic expressions (including integer division)
	Strings
	Classes and objects
		Object properties
		Object methods		
2.  Conditional Statements
	Decision Trees
	General form of conditional statement
	Using if ... elif ... else
	Nested conditionals
	Logical Expressions
		Relational operators (<, >, etc.)
		Logical operators (and, or, not)
3.  Using Turtles to draw
	Naming a Turtle object
	Using Turtle methods:
		forward(distance)
		backward(distance)
		left(angle)
		right(angle)
		up( )
		down( )
		goto(x, y)
		circle(radius)
4.  while loops
	General form of a while loop
	Using a counter in a while loop
	Keeping track of variable values in a loop
	Using compound conditions		
5.  Strings
	Concatenating strings
	Finding the length of a string
	Accessing a character at a given position in the string.
	Accessing a substring of a string	
	Operations with strings
	string methods
6.  Lists
	Accessing values in the list
	Operations with lists
	List methods
7.  for loops
	General form of a for loop
	Execution of a for loop
	Using range( ) to create a list of integers
	Writing a count-controlled while loop as a for loop
	Using for loops with lists
	Changiing values of a list with a for loop

Practice Problems
The following problems are intended to help you study for the exam.

1) A boolean is a data type that has a value of True or False.
Given these boolean variables:
x = True, y = False, z = True

What is the value (True/False) of each of the following?

i)  x and (y or z)


ii) (not x) or  (not(y and z))


iii) y or (x and not z)

Prompt the user to input a number.
Input the number from the keyboard
If the number is less than 100, write:
	XX is a low number.
where XX refers to the number inputted by the user.
Otherwise, write:
	XX is a high number.

3) a) What is the value of sum after the execution of the following code?

	sum = 0
	counter = 1
	while counter < 6:
		sum = sum + 2 * counter
		counter = counter + 1
	print sum

b) Re-write the above code using a for loop instead of a while loop

4) What is the output of the following code fragment (mySentence and partial are both strings)?

	mySentence = "It was a dark and stormy night"
	partial = mySentence[10:13]
	print partial	

• a)

           #Program Error1
           number = raw_input("Please enter a number: ")
           number = number/2.0
           print number
  

  
  

• b)

          #Program Error2
          response = raw_input("Do you like chocolate? ")
          if response == "yes":
              print "Me too!"
          	else:
              	print "That's too bad."
  

  
  

• c)

           #Program Error3
           secret = "mont105S"
           response = raw_input("Enter the password: ")
           if response = secret:
           	print "Access granted."
           else:
           	print "Access denied.   
  

  
  

• d)

           #Program Error4
           count = 0
           while count < 10
           	print count
           	count = count + 1
  

6)  Consider the following while loop:
	sum = 0
	count = 5
	while count <= 12:
		sum = sum + count
		count = count + 2

a) Fill in the following table for the values of count and sum each time through the loop (there may be more rows than you need in the table):

b)Write a for loop that does the equivalent of the above loop.

  7) Consider the following Python code:

        sum = 0
        for i in range(1, 5):
              sum = sum + i
        print sum

  8) Fill in/write the necessary code for the following decision tree.

#program catCheck.py
#Your code goes here

9) Fill in the necessary code to fill in the depositList array with deposit amounts entered by the user. You should keep track of the sum of all the deposits made, so that the print statement at the end of the program makes sense. You can assume there are exactly 100 deposits made.

#Program deposit.py
depositList = [ ]
sum = 0
#your code goes here













print "The sum of the deposits:", sum