Thread: reference doesn't work?

Hi folks,

I have the following code of which I don't understand why the reference 'q' doesn't work:

Code:

#include <cstdlib>
#include <iostream>

using namespace std;

int main()
{
    int n;
        
    cout<<"enter number of items: ";
    cin>>n;
    
    double *p = new double[n];
    double &q = *p;
        
    for (int i=0;i<n;i++) {
    q[i] = i;
    }
    
    cout<<"The first item is: "<<q[0]<<endl;
    cout<<"The last item is: "<<q[n-1]<<endl;
    
    
    delete [] p;
    
    
    system("PAUSE");
    return EXIT_SUCCESS;
}

The Bloodshed Dev C++ linker said for the line:

Code:

 q[i] = i;

Code:

19 invalid types `double[int]' for array subscript

However when I dropped the use of 'q', the program works fine. Is there anything wrong when I use a reference in such a context?

Thanks a lot in advance...

it only added the following error message:

Code:

14 invalid initialization of reference of type 'double&' from expression of type 'double*'

Originally Posted by siavoshkc

double &q = *p;
should be

double &q = p;

I have no means to reference a vector except using the pointer?

Originally Posted by siavoshkc

q is not array you can't use it as an array like q[index]. Use a pointer instead of a reference.

it should be:

Code:

 double *q=p;

and everything works fine. Thanks!
However I still don't get it: is reference operator not applicable in this context? (therefore it can only be used for referencing a single variable? That's uncomfortable...)

Originally Posted by siavoshkc

Why not using pointer?
Just change
double &q = *p;
to
double *q=*p;

and everything will work fine.

>> That's uncomfortable.
Why? What do you expect to be able to do with a reference that you cannot do with a pointer?

I CAN do with a pointer; that's where the uneasiness comes from: why can't I do with a reference? What's wrong?

Originally Posted by Daved

>> That's uncomfortable.
Why? What do you expect to be able to do with a reference that you cannot do with a pointer?

...looks opaque at a first glance though...

[QUOTE=Mario F.]If you really want a reference you should declare it like so:

Code:

double *&q = p;

And it will work fine. q is a reference to a pointer to double.