What are the differences between pass-by-reference and pass-by-value?

What are the differences between pass-by-reference and pass-by-value?

Pass-by-value means a copy of the variable is passed, while pass-by-reference passes the variable's address.

Can you give me an example of each?

Sure! In pass-by-value, if you change the value in the function, the original variable remains unchanged. In pass-by-reference, changes affect the original variable.

Which one is generally preferred in programming?

It depends on the context. Pass-by-value is safer as it protects the original data, while pass-by-reference is more efficient for large data structures.

Are there any languages that use only one of these methods?

Yes, for example, Java uses pass-by-value for primitives and pass-by-reference for objects, while Python uses a model that can be seen as pass-by-object-reference.