CS5nm Midterm Exam 1
E01, 08F, Phill Conrad, UC Santa Barbara
10/24/2008

Name: ________________________________________________________

Umail Address: __________________________________@ umail.ucsb.edu

Please write your name only on this page. That allows me to grade your exams without knowing whose exam I am grading.

This exam is closed book, closed notes, closed mouth, cell phone off,
except for:

• You are permitted one sheet of paper (max size 8.5x11") on which to write notes
• These sheets will be collected with the exam, and might not be returned
• Please write your name on your notes sheet

There are 100 points worth of questions on the exam, and you have 50 minutes to complete the exam.

A hint for allocating your time:

• if a question is worth 10 points, spend no more than 5 minutes on it
• if a question is worth 20 points, spend no more than 10 minutes on it
• if a question is worth 40 points, spend no more than 20 minutes on it
• etc.

1. (20 pts) Write a Python function definition that takes the radius and height of a cone as parameters, and returns the volume of that cone. The formula for volume of a cone, in math notation, is v =¹/₃πr²h. You may use math.pi as the value of pi, and assume that the statement import math has already been included in the Python source file.
   
   
   
   
2. (20 pts) Write a Python function definition that takes two parameters, each of which is a tuple representing an (x,y) point. Return the slope of the line that connects those two points. The formula for slope, in math notation is shown below. (For this exam question, don't worry about what happens if the denominator is zero.)
   
   
   Your function should pass these test cases:
   
   check_expect("slope test 1",slope((0,0),(4,3),0.75)
check_expect("slope test 2",slope((1,1),(3,3),1.0)
check_expect_within_tolerance("slope test 3",slope((0,0),(3,4),0.333333,0.0001)
   
   
3. (30 pts) Fill in the table below, according to these instructions:
   • The first column describes a Python expression
   • In the second column, fill in a Python expression that matches the description in the first column
   • In the third column, fill in the value of the expression you put in the second column. If that expression involves variables, put the values you assumed for those variables in the fourth column.
   • The first row is filled in as an example.

   Description	Expression	Value	Variables (if any)
   An expression involving the addition operator, one variable, and one int value	x + 1	3	x=2
   An expression involving the ** operator
   An expression involving an operator that has a value of type string
   An expression of type bool (Boolean)
   An expression involving the multiplication operator, one variable, and where the result is of type float
   An expression involving one addition operator and one multiplication operator

4. (15 pts) Listed below is an session from IDLE, showing interaction between a user and the Python shell. The response from the shell at various points has been replaced with blanks. Fill in the blanks with what the Python shell would print.
   
   If the blanks are too small, you can write your answers beside them.

   >>> x = 3
   >>> y = 7
   >>> x * 5
   
   _______
   >>> y / 5
   
   _______
   >>> y / 7
   
   _______
   >>> y / 8
   
   _______
   >>> x + 2 * y
   _______
   >>> x + y
   
   _______
   >>> x = x + 2
   >>> x
   
   _______
   >>> x + y
   
   _______
   >>> y
   
   _______
   >>> x
   
   _______
   >>> "x"
   
   _______
   >>> "y" + "x"
   
   _______ 
   >>> "y" * 3
   
   _______
   >>> x * 2
   
   ________
   >>> x ** 2
   
   ________
   >>> 

5. (10 pts) Suppose your friend is taking CS5NM, and says:

   I'm still not 100% clear on the difference between a function call and a function definition. I understand how they look different on the page—I mean, the function defintion has the word def in it, duh—and the function call doesn't. But I'm not sure I understand what they mean. Can you explain it?

   How do you explain the difference to your friend in plain english?

6. (5 pts) Which of the following are legal variable names in Python? For each, circle yes or no:
   
   
   

   lunch_break	Circle:       yes        no
   onceAnd4All	Circle:       yes        no
   twice bitten	Circle:       yes        no
   3timesALady	Circle:       yes        no
   def	Circle:       yes        no
   my-friend	Circle:       yes        no

End of Exam

Total points: ?