Lab 4: Strings, Loops and Recursion

Logistics

• Due: Tuesday, September 19th no later than 11:59 p.m.
• Partner Information: Everyone is required to complete this assignment with a partner who is in your same lab section. Your lab TA will help you find a partner at the start of your lab period if you don't already know who your partner will be.
• Submission Instructions: Upload your solution, entitled YourFirstName-YourLastName-PartnerFirstName-PartnerLastName-Lab4.py to the BrightSpace Lab 4 Dropbox. Note: Only one person needs to submit a solution. If you both submit a solution, the submission that will be graded is the one from the partner whose last name comes alphabetically first.
• Deadline Reminder: Once this deadline passes, BrightSpace will no longer accept your Python submission and you will no longer be able to earn credit. Thus, if you are not able to fully complete the assignment, submit whatever you have before the deadline so that partial credit can be earned.

Learning Outcomes

• Gain experience with strings.
• Gain experience with loops.
• Gain experience with recursion.

Assignment

• Download lab4.py and rename it according to the instructions above.
• Modify the program by adding the four missing functions. The functions are described in the grading section below.
• If the missing functions are implemented correctly, this output will appear when the user enters how now brown cow for the first string and ow for the second string. Note: Your solution should work for any pair of strings.

Grading - 10 points

Note: For this lab, you are required to work with a partner and submit a joint solution. If you submit a solution without a partner, 3 points will be deducted.

• 4 points - A function named concatenation_loop is implemented that has two string parameters. The function must return the concatenation of the two strings using an appropriate loop. You may use the built-in concatenation operator (+) to concatenate a string and a character. However, you may not use it to concatenate two strings.
• 1 point - A function named concatenation_recursion is implemented that has two string parameters. The function must return the concatenation of the two strings using recursion. You may use the built-in concatenation operator (+) to concatenate a string and a character. However, you may not use it to concatenate two strings. Do not use any loops in the solution.
• 4 points - A function named occurrences_loop is implemented that has two string parameters. The function must return the number of times that the second string parameter appears in the first using an appropriate loop. The built-in count function may not be used.
• 1 point - A function named occurrences_recursion is implemented that has two string parameters. The function must return the number of times that the second string parameter appears in the first using recursion. Neither the built-in count function nor any loops may be used.

If Time Remains

If you want to work with a partner on Program 2 (due 9/29), use this time to identify a partner or ask your lab TA to help you find someone. Note: For the vast majority of computing jobs and internships, the ability to work with one or more teammates is a crucial skill!