Assignment 1 PyCharm IDE

Learning Objectives:
● Continue to explore the PyCharm IDE
● Practice editing, building, and running Python programs.
● Learn to interpret error messages from the PyCharm IDE in order to help to debug your
computer program.
● Learn the rules for naming identifiers in Python
● Learn to keep an error log
● Write your first program
Background and Terminology
To create a computer program, one needs an editor to create the source code of the program.
The source code contains the sequence of steps the programmer designed for the program (the
algorithm ), written in a specific language. The computer cannot yet execute this code at this
stage because it is written in a high-level language designed for human readability, and it must
be translated for the computer to understand it. This translation happens via the IDE or an
interpreter.
Rarely do programs work the first time they are written. We must have some way to check what
happens when our program fails to work correctly, due to a programming error called a bug .
According to folklore, the first computer "bug" was an actual moth discovered by Grace Hopper
in 1947 that was trapped between two electrical relays of the Mark II Aiken Relay Calculator and
caused the machine to crash . A "bug" is a term used to describe a situation where a program,
for a variety of reasons, does not do what it is expected to do. Some bugs are found by the
IDE, others require a utility program called a debugger to find and correct these mistakes, and
some must be found by you, the programmer. Debuggers enable programmers to stop runningtheir program at any point and examine the contents of any of the variables to ensure that their
values are what they are expected to be.
Define each of the bold words in the text
above, in your own words:
● Source code
● Algorithm
● IDE
● Interpreter
● Bug
● Crash
● Debugger
● Variables
If you need to look up a word, feel free to do
so, but cite your sources (even if it’s the
course textbook)!
1. Source Code: The basis of a program
that allows it to run
2. Algorithm: a list of steps that can be
taken to achieve a result.
3. IDE: A program can be used to
develop software
4. Interpreter: Someone or something
that translates information in a way in
which you can understand it.
5. Bug: Anything that causes a problem
in a program
6. Crash: This is what happens when
there are too many problems and a
program either closes suddenly or
stops working altogether
7. Debugger: A program that analyzes
and fixes bugs in programs
8. Variable: Something that when
applied can change the outcome of
something else
Instructions
1. Download the following file: t0_chocolate.py. You may recognize it from T0.
2. Open the file in PyCharm. Refer back to the T0 instructions if you need help
remembering where to place the file so it is part of a PyCharm project and how to open
them.
3. Run the program a few times, taking note of the interactions that occur in the Python
Console.
Now, let’s create some bugs.
Fundamentals of Programming Errors (bugs)
There are many kinds of programming errors or bugs:
● A syntax error is an error in the grammar, structure, or order of the elements in the
source code. Syntax errors are typically detected by the IDE and flagged with a red
squiggly underline in PyCharm. Normally, your program will not run at all with a syntax
error in the source code.
● Run-time errors are generally detected by the IDE, but only when the user attempts to
run the program. One standard example of a run-time error is where the source code
has an instruction to divide a value by zero. The syntax may be correct (hence, no redsquiggly line), but the program will terminate early (i.e., crash) if the denominator has the
value of 0. Usually run-time errors will cause the running program to crash, but they
sometimes just generate warnings during the program execution.
● Semantic errors or logic errors are the most subtle, where the program is coded
correctly and does not crash but do not perform the correct operation to produce the
expected results. Errors of this kind cannot be found automatically by the IDE or easy to
determine by the program's output. They are usually due to errors in the design or how
the algorithm was translated into the source code.
Creating an Error Log
This assignment is designed for you to become more familiar with the error detection built into
the PyCharm IDE. In particular, you will create a catalog of typical errors that may arise, and this
document may hopefully help you in the future to identify the actual problem based upon the
error message the IDE produces.
Complete each action below in the t0_chocolate.py file, and log the response from PyCharm on
the right. Indicate three things:
1. Classification: Either SYNTAX , RUNTIME, SEMANTIC/LOGIC (only record the first
error, with a very brief explanation) or NONE (for no errors). Remember that just
because the IDE doesn't catch it, does not mean there is not an error.
2. Error Indication: Note the first error indication or message if one appears. Then copy or
describe the resultant error and/or warning message you got into your Error log below.
3. Correspondence : How obvious was it to you that you made an error? In other words,
did PyCharm identify the actual problem? Was the message clear, or cryptic and hard to
understand? Briefly explain why or why not?
4. Finally, repair each change that you just made to restore the program to its original state.
Thus, after making each of the charges, you will begin again with the original working
code. The undo command (Ctrl + Z) is often useful here.
Example 0:
Change: Remove the second quotation mark from
the line:
entered_name = raw_input("Please
enter your name: ")
Classification: Syntax Error because it
is a grammatical error
Error Indication(s): On the line where
the error exists, a red squiggly line
appeared under the text. When I hold my
mouse over the text, it says “Missing
Closing Quote [“]”. The next line also has
a red squiggly at the end of it, that says
“End of statement expected”
Correspondence: Excellent. The
problem we created was that the string
never ended. The warning symbolappeared on the correct line and the
caret appeared just after where the
problem was.
1. Change the line:
oz_per_lb = 16
to
16 = oz_per_lb
Classification: syntax error
Error Indication(s): cannot assign to
literal
Correspondence: I do not know what
this means. I don’t know what the “literal”
is.
Remove the word int from the line:
num_lbs = int(raw_input("How many
lbs of chocolate in a box? "))
Classification: Syntax Error
Error Indication(s): TypeError:
unorderable types: str() int()
Correspondence: I understand this.
The program is trying to compare a
string variable with a integer variable
which it cannot do.
Change both occurrences of oz_per_lb to
16oz_per_lb
Classification: syntax error
Error Indication(s): end of statement
expected
Correspondence: I think that it expects
the line of code to end directly after the
16
Change the line
print("Hello "+ entered_name+"! \n")
to
print("Hello "+ entered_name+"! /n")
Classification: none
Error Indication(s): The /n showed up
in the program when run
Correspondence: Instead of starting a
new line it just printed the /n
Change the line
if oz_choc 500:
by changing the to a <
Classification: noneError Indication(s): It flops the result of
whether you are a chocaholic or not.
Correspondence: I understood this
fully. I knew exactly what was going to
happen.
Remove the colon from the line
if oz_choc 500:
Classification: syntax error
Error Indication(s): unexpected indent
Correspondence: The print command
was indented when it shouldn’t be
Change the algorithm by changing the line
oz_choc = lbs_choc * oz_per_lb
to
oz_choc = lbs_choc / oz_per_lb
Classification: none
Error Indication(s): The resulting
number was significantly lower than it
should have been.
Correspondence: I understand this
because instead of multiplying to get
your final answer, you are dividing.
Deliberately create a syntax error which differs
from all of the above. Describe how to create the
error and then create an error log for the error.
Change: Remove the 6th apostrophe
in line 40
Classification: Syntax error
Error Indication(s): Missing end quote
Correspondence: It is missing that
apostrophe to finish the quote
Deliberately create a semantic/logic error which
differs from all of the above. Describe how to
create the error and then create an error log for
the error.
Change: Remove line 35
Classification: Semantic
Error Indication(s): lines 34 and 36 do
not print if the number is below 500 and
if it is above 500 both lines print Correspondence: It creates a situation
in which lines 34 and 36 will only be
printed if the number is above 500.
Deliberately create a run-time error which differs
from all of the above. Describe how to create the
error and then create an error log for the error.
Change: add a /0 after the 500 in line 35
Classification: run-time
Error Indication(s): ZeroDivisionError:
division by zero
Correspondence: I understand this
because the program is trying to divide
500 by 0 which can’t be done.
Your First Code - Python Conditionals
“Everything has beauty, but not everyone sees it” - Confucius1
The Chinese Zodiac, according to its Wikipedia page, is a “ classification scheme that assigns
an animal to each year in a repeating twelve-year cycle.” The scheme is quite complex, so we
will only be considering a small portion of the scheme for this assignment. Namely, the
relationship between the twelve animals, and your year of birth:
Animal Birth Year
Rat …, 1972, 1984, 1996, ...
Ox …, 1973, 1985, 1997, ...
Tiger …, 1974, 1986, 1998, ...
Rabbit …, 1975, 1987, 1999, ...
Dragon …, 1976, 1988, 2000, ...
Snake …, 1977, 1989, 2001, ...
Horse …, 1978, 1990, 2002, ...
Goat …, 1979, 1991, 2003, ...
Monkey …, 1980, 1992, 2004, ...
Rooster …, 1981, 1993, 2005, ...
Dog …, 1982, 1994, 2006, ...
Pig …, 1983, 1995, 2007, ...
So, for example, I was born in 1982, which makes me a dog. Try to keep the jokes to a
minimum…
In class, we took a brief tour of the following code: A1_pets.py. There are lots of good hints in
this code that you’ll want to use as you solve the problem for this assignment.
Your tasks
You have three tasks for this assignment. I suggest solving them in order, and not moving on
from each subtask until you solve the prior task.
Download this starter code, A1_stubs.py, which includes notes for all tasks. HOWEVER, keep
reading this document to make sure you complete all tasks!
Task 1
1. Create a Python program that asks the user for input. Namely, ask the user to put in the
year they were born.
2. Print to the screen that user’s Chinese Zodiac animal that corresponds to their birth year.
For me, you would print something like “Your animal is the dog!”
NOTE : For now, you only need to consider years between 1985 and 1994, as the vast
majority of the class will fall in that range.
Task 2
In addition to the Chinese Zodiac showing your animal, it also shows who you are “most
compatible” with, on this compatibility grid. So for example, I’m a Dog (1982), and if you are a
Dragon (1988), we are not a good match. Sorry Dragons!
(I’ll still try to get along with you in the class!)
Alternatively, you also have animals you are highly compatible with. In my case, I am most
compatible with the Rabbit (1987), Tiger (1986), and Horse (1990). We’re going to get along
great!Implementing ALL of these combinations would be far too much, especially this early in the
course. Also, it’d very tedious by the time you got to the end, and you wouldn’t learn more by
doing all of them. So, you will only need to implement the “No match” and “Best match”
for your own animal. So, I would only implement the “Dog” column on the table, as I described
above.
1. In the same Python program, after the Task 1 code, ask the user to input a friend’s birth
year.
2. Print to the screen that friend’s Chinese Zodiac animal that corresponds to their birth
year. Again, only worry about the years between 1985 and 1994.
Task 3
1. Using the compatibility grid, print out one of two things:
a. If your animal and your friend’s animal are a “No match”, print to the screen a
witty message indicating why you aren’t a good match.
b. If your animal and your friend’s animal are a “Best match”, print to the screen an
even wittier message about why you are the best of friends.
c. Else, print to the screen the wittiest message about why you are “okay” friends.
A sample output is provided here, so you can see one possible output of your program.
Additional challenges (not graded )
1. Make the program work for any year, not just 1985 through 1996.
2. Make the program work for the entire compatibility table.
3. Minimize the number of if/elif/else statements.
4. Implement the month, day, and/or hour animal signs, as described in the Wikipedia page