CMPSC-132: Programming and Computation II
Homework 3
100 pts
Instructions:
- The work in this assignment must be completed alone.
- The file name must be HW3.py (incorrect name files will get a -10 point deduction)
- When any function returns an error, it must be a string containing “error”
- Do not include test code outside any function in the upload. Remove all your testing code
before uploading your file. That includes user-defined input()
Goal:
Modify the function calculator(expr) so that it supports exponentiation. This operation will be
represented in the string as ^ unlike Python’s **. An example of a valid expression is “-5 + 60 /
3^3 * 4 - 2 * 4 ^2”. In this assignment, more than one consecutive exponentiation is not
supported.
Notes:
- This is a straightforward upgrade of HW2 and there is no starter code
- You will also have to modify findNextOpr and exeOpr to include ^ (which is ** in Python)
- In your submission, include all functions in your HW3.py script (calculator, findNextOpr,
isNumber, getNextNumber and exeOpr)
Function requirements:
The function must return the computed value if expr is a correct formula, otherwise it must
return an error message.
When any function returns a numeric value, it must be float
Do not use exec or eval function. You will not receive credit if your program uses any of the
two functions anywhere
All five functions from HW2 must work
Grading Notes:
- The grading script will feed 5 randomly chosen test inputs, each for 20 points. One of them
will be an input that should cause an error such as “4 * / 2 + 5 ^”, whose expected returned
value is an error message.
Example:
calculator(“-5 + 60 / 3^3 * 4 - 2 * 4^2”)
-28.11111111111111
calculator("4^2 / 2^2")
4.0
calculator("-4^ / 2^2")
'error'
Deliverables:
Include all the functions in your script named HW3.py. Submit it to the HW3 CANVAS
assignment before the due date
