Computer Science – 12.3 Program Testing and Maintenance | e-Consult

Here are three potential error types and methods for detection:

• Syntax Error: This occurs when the code violates the grammatical rules of the programming language. In this case, a syntax error might be present in the recursive function definition, such as incorrect indentation, missing colons, or improper use of keywords.
  

  Detection: The Python interpreter will flag a syntax error during the compilation/parsing phase. Integrated Development Environments (IDEs) like VS Code or PyCharm will highlight syntax errors as the code is being written.

• Logic Error: This is an error in the algorithm or the way the code is structured, leading to incorrect results even if the syntax is correct. A common logic error in a factorial function is an incorrect base case (e.g., not handling the case where n=0 correctly) or an incorrect recursive step. For example, the recursive call might be using the wrong argument or not correctly multiplying the result.
  

  Detection: Thorough testing with a variety of inputs, including edge cases (e.g., 0, 1, 5, 6, 10), is crucial. Using a debugger to step through the code and examine the values of variables at each stage can also reveal logic errors. Code reviews by other programmers are also highly effective.

• Runtime Error: This occurs during the execution of the program, often due to unexpected conditions. A runtime error could arise if the recursion depth is exceeded (leading to a stack overflow) or if the input is invalid (e.g., a negative number is passed to the function, which is not handled).
  

  Detection: Using a try-except block to catch potential exceptions (e.g., RecursionError, ValueError) can help handle runtime errors gracefully. Input validation (checking that the input is a non-negative integer) before calling the factorial function can prevent invalid inputs from causing runtime errors. Also, monitoring the program's memory usage can help detect stack overflows.