Sample Midterm

These are sample questions that are very similar to the ones I will ask on the midterm.

1. Which of the following Python identifiers are legal variable names? For those that are not, say why not.
   1. x
   2. Celsius
   3. spam3
   4. <hello>
   5. question?
2. What is the data type (int, float, string, boolean) of the following? Please evaluate them.
   1. 3.9 + 6
   2. 5 + 1 > 7 or 2 == 1 + 1
   3. int("3")
   4. 7 / 2
   5. 8 // 3
3. Write the following formulas in Python.
   1. a²
   2. 
   3. 
4. What does the following program print?

   for i in range(1, 5):
   	x = (-1) ** i * i
   	print(i, x)
   

5. Convert the following into a “for” loop.

   i = 1
   while i <= 10:
   	print(i)
   	i += 3
   

6. When I ran the following program:

   x = int(input("Enter a number: "))
   y = 1 / x
   print("The reciprocal of", x, "is", y)
   

   I got the following error message:

   Traceback (most recent call last):
     File "x.py", line 2, in <module>
       y = 1 / x
   ZeroDivisionError: int division or modulo by zero
   

   What was the specific error? Where did it cause the exception? And what did the user type?

ECS 10, Basic Concepts of Computing Fall Quarter 2012