How do you pass a class by reference in C++?

Pass-by-reference means to pass the reference of an argument in the calling function to the corresponding formal parameter of the called function. The called function can modify the value of the argument by using its reference passed in. The following example shows how arguments are passed by reference.

Should you always pass by reference C++?

It used to be generally recommended best practice1 to use pass by const ref for all types, except for builtin types ( char , int , double , etc.), for iterators and for function objects (lambdas, classes deriving from std::*_function ).

Can C++ pass reference?

C++ makes both pass by value and pass by reference paradigms possible. You can find two example usages below. Arrays are special constructs, when you pass an array as parameter, a pointer to the address of the first element is passed as value with the type of element in the array.

What is the main advantage of passing arguments by reference in C++?

Advantages of passing by reference: References allow a function to change the value of the argument, which is sometimes useful. Otherwise, const references can be used to guarantee the function won’t change the argument.

Are there any examples of pass by reference in C?

C doesn’t support pass-by-reference. Here are two C++ examples of pass by value: When ex.1 is called, the constants 2 and 2 are passed into the function by making local copies of them on the stack. When the function returns, the stack is popped off and anything passed to the function on the stack is effectively gone.

How does a class pass object by reference work?

The function uses this pointer (which is simply a memory address) to dereference and change the value at that memory address in order to “return” the result. Since the function needs a memory address as a parameter, then we must supply it with one, which we do by using the & “address-of” operator on the variable result.

When do you pass a pointer by value in C?

Its value is the address of i. When you call f, you pass the value of p, which is the address of i. No pass-by-reference in C, but p “refers” to i, and you pass p by value. Because you’re passing a pointer (memory address) to the variable p into the function f. In other words you are passing a pointer not a reference.

When do you pass a reference to a function?

In the examples from the previous page, we used normal variables when we passed parameters to a function. You can also pass a reference to the function. This can be useful when you need to change the value of the arguments: