Arizona State University (ASU) CSE240 Introduction to Programming Languages Midterm Practice Exam

In programming, the distinction between pass-by-value and pass-by-reference revolves around how data is transmitted to functions or methods. When using pass-by-reference, the function receives an access point to the original variable, meaning any changes made to that variable within the function alter the original data. This allows for more efficient memory usage since only the reference to the variable is passed, rather than a copy of the actual data.

This method is particularly useful when you want functions to manipulate data directly or when dealing with large data structures, as it avoids the overhead of copying large amounts of data. It enhances performance and enables the function to modify the state of objects without returning any data back to the caller.

In contrast, pass-by-value involves sending a copy of the variable to the function. Therefore, any modifications within the function do not affect the original variable since the function operates on a duplicate. This approach is safer in terms of data integrity but can lead to inefficiencies due to the time and space costs associated with copying data.

Understanding this difference is important for effective programming, particularly when designing functions that need to modify data or when performance implications are a concern.