Passing array by value

Question

Is it possible to pass an array by value to a C++ function?

If it is, how would I do that?

Answer 1

Definitely:

void foo(std::array<int, 42> x);

Answer 2

Yes, you can. You can implement it by using a pointer as the argument, but in the function body, you can use the copy mothord (the exact name I can't remember) to copy it.

Answer 3

Normally passing an array to a function makes it decay to a pointer. You implicitly pass the (start-)address of the array to the function. So you actually can't pass an array by value. Why don't you use va_args if you want to pass the contents by value?

Answer 4

If by array you mean raw array, then the answer is No. You cannot pass them by value either in C or C++.

Both the languages provide a workaround, where you can wrap a struct around that array and pass its object. Example:

struct MyArray { int a[100]; };
...
struct MyArray obj; // `obj.a[]` is the array of your interest
foo(obj);  // you have passed the `a[]` by value

In C++, such structs are readily available in form of std::vector and std::array.