As parameters to a function, class objects can be passed by reference only.

Question

Problem :

A simple question for which I want to find the answer here.

“As parameters to a function, class objects can be passed by reference only.”

void myRefFunction(type myRefVariable)
{
}

void main()
{
    myRefFunction(myRefVariable);
}

For a simple data types like int, float, etc. a function is called by value.

But if myRefVariable is the array, only a starting address is passed (even though the function is the call by value function).

If myRefVariable is the object, also only a address of a object is passed rather than creating the copy and passing it.

So question is does C++ pass the object by reference or value?

Answer 1

Arguments are passed by the value, unless a function signature specifies it  otherwise:

·In a void foo(type arg), arg is passed by the value regardless of whether type is the simple type, the pointer type or a class type,

·In a void foo(type& arg), arg is passed by the reference.

In case of the arrays, a value that is passed is the pointer to a first elements of a array. If you know a size of an array at compile time then you can pass the array by reference as well: void foo(type (&arg)[10]).