What is the difference between pass by value and pass by reference in C++?

What is the difference between pass by value and pass by reference in C++?

In C++, pass by value means passing a copy of the variable's value, while pass by reference passes the variable itself.

Can you give me an example of each?

Sure! For pass by value, if you modify the parameter inside a function, the original variable remains unchanged. For pass by reference, changes to the parameter affect the original variable.

Which one is more efficient?

Pass by reference is generally more efficient for large objects since it avoids copying the entire object.

Are there any downsides to using pass by reference?

Yes, using pass by reference can lead to unintended side effects since the original variable can be modified.