References Good references are required
to get a job, loan or possibly even a date. You should never
lie about references on your resume because they might be
checked. What does this have to do with C++? :-? Nothing, but
I can't help but create bad puns, and it gave me an
opportunity to use the "puzzle mouth" emoticon. In C++, a reference
is an alias to a variable.
The real usefulness of references is when they are used to
pass values into functions.
They provide a way to return values from the function, as will
be shown in the next lesson.
For now, we'll examine how to create and use
references.
A reference is an alias to an object.
Here's some code that shows how to create a reference.
int val; // Declares an
integer int &rVal =
val; //
Declares a reference to the integer object val
| Notice the use of the "&"
before the reference name. In this context, the "&" is
called the reference operator. It indicates that rVal is a
reference rather than an ordinary object.
In earlier lessons, the "&" was used to obtain an address
of an object. In that context, the "&" was called the address
of operator. The address of operator is used to obtain an
address, typically, to initialize a pointer.
Here's an example.
int val; // Declares an
integer int *pal =
&val; //
Declares a pointer and initializes it to the address of
val. | A reference is not a
unique object. It is merely an alias or synonym for another
object. The reference identifier (name) may be used anywhere
the referred identifier may be used. Any changes to the
reference also apply to the original object. Changes to the
original object are also seen through the
reference.
#include <iostream> using namespace
std;
int
main() {
int val =
1; int &rVal =
val;
cout << "val
is " << val <<
endl; cout << "rVal is
" << rVal <<
endl;
cout <<
"Setting val to 2" <<
endl; val =
2;
cout << "val is
" << val <<
endl; cout << "rVal is
" << rVal <<
endl;
cout <<
"Setting rVal to 3" <<
endl; rVal =
3;
cout << "val is
" << val <<
endl; cout << "rVal is
" << rVal <<
endl;
return 0; }
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