In pass-by-reference, what happens when you pass a variable to a function?

• A. A copy of the value is passed; modifications inside the function do not affect the original
• B. A reference to the data is passed; modifications inside the function affect the original
• C. The value is passed as a string
• D. The value is passed via a global variable

Answer: (B)

Pass-by-reference means the function gets a direct handle to the original variable, not a separate copy. Both the caller and the function reference the same memory location, so any change made inside the function alters the original data. This avoids copying the value, which can be more efficient for large data, but it also means the function can unintentionally modify the caller’s variable. In contrast, passing by value would copy the value into the function, so changes inside don’t affect the original.