CODEWITHSUNDEEP
c++pointersreference
Ammy
Ammy

Reputation: 33

Pointer address as reference in function

I've got one general question, why can't I pass the the pointer's address as a reference?

void domdom(string &foo)
{
 foo = "";
}

string fooso = "blabal";
string* p_fooso = fooso;

domdom(p_fooso); // <-- why is that not possible? And what should I pass to be able to modify foosoo?

I know I could change the function domdom to accept (string* foo), but is it also possible to modify the string fooso in the function by using the pointer to it and the given function?

Upvotes: 3

Views: 69

Answers (3)

user4815162342
user4815162342

Reputation: 155046

Pointers and references are similar under the hood, but are used differently, which is why mixing them by implicit conversion is not allowed by C++, to avoid confusion.

However you can always explicitly convert a reference to a pointer, and vice versa, without incurring the overhead of a copy. For example, if you call the function as domdom(*p_fooso), you will get the desired effect, i.e. the function will receive reference to the exact object you'd get by dereferencing the pointer.

Upvotes: 1

varun
varun

Reputation: 2107

Just declare p_fooso as a string reference type. You might want to rename variable as r_fooso!

string& r_fooso=fooso;

Upvotes: 2

Emil Laine
Emil Laine

Reputation: 42838

why can't i pass the the pointer's address as a reference?

Because that's how the language is defined.

Instead, you can dereference the pointer to get a reference to the string:

domdom(*p_fooso);

or, pass the actual object directly:

domdom(fooso);

Also note that string* p_fooso = fooso; doesn't compile. You have to write string* p_fooso = &fooso;.

Upvotes: 6

Related Questions