Where does the reference variable gets stored [duplicate]

Question

I know that reference does not take any memory it will point to the same memory location which it is referencing. for eg

int i=10;
int &r = a;

suppose i points to the memory location 1000 so in this case r will also point to the memory location 1000. But in C++ whenever we are declaring a variable it will get stored in the memory at some location. In this case r is pointing to some location but it should be stored somewhere in memory via some internal representation. thanks in advance.

Answer 1

That is left unspecified, and for good reason. The real answer is: it depends on the reference. It can be represented as a normal pointer, or it may not exist at all.

If you have a function-local reference with automatic storage duration, such as this r:

void foo()
{
  int x[4] = {0, 1, 2, 3};
  int &r = x[1];
  // more code
}

then it will probably not take up any space at all. The compiler will simply treat all uses of r as an alias for x[1], and access that int directly. Notice that such alias-style references can also result from function inlining.

On the other hand, if the reference is "persistent" or visible to other translation units (such as a data member or a global variable), it has to occupy some space and be stored somewhere. In that case, it will most likely be represented as a pointer, and code using it will be compiled to dereference that pointer.

Theoretically, other options would also be possible (such as a lookup table), but I don't think those are used by any real-world compiler.