Question

Task 2: Debugging and writing functions

1. In IDLE, use the File -> New Window menu option to open a new editor window for your program, and save it using the name hw4Task2.py. Make sure to specify the .py extension.
2. Copy the following (buggy) code into that file:

def mysum(x, y)

""" takes two numbers and returns their sum """

    total = x + y

    print(total)

3. Save the file using Ctrl-S. Then try to run it using F5. What happens?
4. This function includes two syntax errors – errors that violate the rules of the Python language. See if you can find and fix them, continuing until you are able to run the file without any error messages. (Create a MS Word file and name it Task2 steps”. Use this word file, to write what you did to fix the errors in this step.)
5. Once you have eliminated the syntax errors, test the function from the Shell as follows:

>>> mysum(44, 67)

>>> print(mysum(10, 7))

What happens? Why?

(Use the MS Word file “Task2 steps”, and write your answer to this step.)

6. Fix the function so that both above tests work as expected.  (Use the MS Word file “Task2 steps” and write what you did in this step.)
7. In hw4Task2.py, write a function named sum_double that accepts two integers as parameters. The function should return the sum of the integers, unless the two values are the same, in which case the function should return double their sum. For example:

                 >>> sum_double(1, 2)

                 3

                 >>> sum_double(3, 2)

                 5

                 >>> sum_double(2, 2)

                 8

Be sure to write a docstring for the function.

After writing the function, test it in two ways:

• Make function calls from the Shell like the ones shown above.
• Copy the following code into your file:

def test():

    """ function for testing """

    test1 = sum_double(1, 2)

    print('first test returns', test1)

    # Add more tests below

This code provides the beginnings of a test function, with lines that call the function with a set of inputs and print the return value. It’s worth noting that this function does not need a return statement, because its sole purpose is to make test calls and print their results.

You should:

• add other test cases to the test function
• run the Python file
• call the test function from the Shell (by entering the call test()) and check that you obtain the correct return values for each test case.

(Use the MS Word file “Task2 steps”and write what you did in this step.)

Answer 1

Task2 Steps:

1. Syntax Error: Invalid Syntax

This error can be fixed adding colon at the end of the first line of function defination.

2. IndentationError: expected an indented block

This error can be fixed by giving the tab space before the doc string.

3. Test case 1: mysum(44, 67)

This test case will work correctly and will give the expected output.

4. Test case 2: print(mysum(10, 7))

This test case is returning None along with printing the output. This can be fixed by changing the last line of the function defination from "print(total)" to "return total".

Modified Code

def mysum(x, y):

    """ takes two numbers and returns their sum """

    total = x + y

    return total

hw4Task2.py

sumdouble function

def sum_double(a, b):
    
    """returns the sum if two integers are not same, otherwise returns double of sum"""
    
    #return double of sum if two numbers are same
    if(a == b):
        return 2*(a+b)
    
    #return sum if two numbers are not same
    else:
        return (a+b)

test function

def test():
    
    """function for testing"""
    
    #first test case
    test1 = sum_double(1,2)
    
    #second test case
    test2 = sum_double(3,2)
    
    #third test case
    test3 = sum_double(2,2)
    
    #print the results
    print('first test returns', test1)
    print('second test returns', test2)
    print('third test returns', test3)

function call

test()

Steps:

1. create the function sum_double which takes two parameters as input.

2. check the condition if both the numbers are equal.

3. return double of sum if both the numbers are equal otherwise return sum.

4. create the function test which tests the sum_double function.

5. write 3 function calls to check the input test cases.

6. print the result of the test cases.

7. call the function test to get the result.

All the function has been given with the heading, also comments has been provided for the reference.

Please execute the code in IDE to get the output.