๐ Topic Summary
Recursion is a powerful problem-solving technique where a function calls itself to solve smaller instances of the same problem. Think of it like Russian nesting dolls; each doll contains a smaller version of itself. In the context of strings, recursion can be used to perform operations such as reversing a string, checking if a string is a palindrome, or searching for a specific pattern. By breaking down the string into smaller substrings and recursively applying the same operation, we can efficiently solve complex string-related problems.
This unplugged activity uses no computers! Weโll explore recursion by manipulating strings manually. This hands-on approach allows you to visualize how the recursive process unfolds, making the concept more intuitive and easier to grasp. By the end of this activity, you'll have a solid understanding of recursion and its applications to string manipulation.
๐ค Part A: Vocabulary
Match each term with its definition:
| Term |
Definition |
| 1. Base Case |
A. The process of a function calling itself. |
| 2. Recursive Step |
B. A sequence of characters. |
| 3. String |
C. The condition that stops the recursive calls. |
| 4. Recursion |
D. A function that calls itself. |
| 5. Recursive Function |
E. The part of the function where the recursive call happens. |
Match the correct letter to the number:
- 1: ____
- 2: ____
- 3: ____
- 4: ____
- 5: ____
โ๏ธ Part B: Fill in the Blanks
Complete the paragraph using the words provided: base case, string, recursion, recursive, substring.
_________ is a technique where a function calls itself. This is especially useful when working with _________. Each time the function calls itself, it usually works on a smaller _________ of the original string. To prevent infinite loops, every recursive function needs a _________ that stops the _________ calls.
๐ค Part C: Critical Thinking
Explain, in your own words, how recursion helps in reversing a string. Can you think of a non-recursive way to achieve the same result? What are the pros and cons of each approach?