Advanced Placement (AP) Computer Science

What might happen if a function receives an unexpected input type?

1. The function will always execute correctly.

2. The function might throw an error or not work correctly.

3. The function will ignore the input type.

4. The function will replace the input with zero.

The correct answer is: The function might throw an error or not work correctly.

When a function receives an unexpected input type, the behavior largely depends on how the function is implemented and the language being used. If a function is designed to handle specific data types, an unexpected type can lead to various issues. For instance, many programming languages perform type checking and may throw an error if the input does not match the expected type. This prevents the function from executing properly, as the operations within the function may not be valid for that type. In addition to throwing an error, unexpected inputs can also lead to incorrect behavior. For example, if a function expects a number but receives a string instead, the arithmetic operations intended for numbers may not yield meaningful results or might even cause the function to crash. It is crucial for functions to validate their input types to ensure robust and predictable behavior. This validation can lead to early detection of issues, making debugging easier and improving the reliability of the code. Other options do not accurately reflect the behavior of functions in programming languages. Functions do not always execute correctly regardless of input, they typically do not ignore input types, and they do not universally replace inputs with zero unless explicitly programmed to do so. Ultimately, the possibility of throwing an error or not functioning as intended is a significant concern when dealing with unexpected input