Give references values?

[Sigge414]

Why is this possible?:

#include <iostream>

using namespace std;

int main(){
	const int &a = 10; //<- this
	return 0;
}

I thought I understood references but this doesn't make sense to me?!


Edit:

#include <iostream>

using namespace std;

int main(){
	const int &foo = 10;
	cout << &foo << endl;
	return 0;}

I am setting the reference foo to represent the memory holding 10 but since 10 isnt a variable(it isnt stored) this doesn't make sense to me.

[Ganado]

Well, the short answer is that you can do that because the standard says so.

It's equivalent to doing something like this:

int temp_foo = 10;
const int& foo = temp_foo;

The usefulness of this really isn't apparent there, but one reason this construct exists is to be able to pass in temporaries to functions that expect const references.

void foobar(int& a) { }
int main 
{
    int b = 3;
    foobar(b); // OK
    foobar(3); // Error
}

The above foobar(3); won't work because you can't make a temporary become a non-const reference.

But if you change it to

void foobar(const int& a) { }
int main 
{
    int b = 3;
    foobar(b); // OK
    foobar(3); // Still OK!
}

Then the function will work, because it allows turning a temporary object (3) into a const reference.

There was a thread like this before, where someone explained it quite well, but I can't find it...