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Reference to class question

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  Reference to class question Nephi Immortal <immortalnephi@gmail.com> - 2011-08-13 08:52 -0700
    Re: Reference to class question Ian Collins <ian-news@hotmail.com> - 2011-08-14 08:43 +1200

#8791 — Reference to class question

Please confirm if my code is valid with no undefined behavior.  When
you create data members, any built-in types such as char, int are
always uninitialized until you tell Constructor function to initialize
them.

What about two data members: x and y in Z class?  Both x and y are
always initialized automatically with memory address before you call
Constructor function.

Reference is like a pointer to set up memory address.  The y in Z
class is always bound to Y class and it can’t be unbound unless you
change from reference to pointer.

struct X
{
	X( int _x, int _y ) : x( _x ), y( _y )
	{
	}

	~X()
	{
	}

	int x;
	int y;
};

struct Y
{
	Y( X& _x ) : x( _x )
	{
	}

	~Y()
	{
	}

	X &x; // reference
};

struct Z
{
	Z( int a, int b ) : x( a, b ), y( x ) // initialized y( x )
	{
	}

	~Z()
	{
	}

	X x;
	Y y;
};


int main()
{
	Z z( 1, 2 );

	return 0;

}

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#8797

On 08/14/11 03:52 AM, Nephi Immortal wrote:
> Please confirm if my code is valid with no undefined behavior.  When
> you create data members, any built-in types such as char, int are
> always uninitialized until you tell Constructor function to initialize
> them.
>
> What about two data members: x and y in Z class?  Both x and y are
> always initialized automatically with memory address before you call
> Constructor function.

They aren't initialised with an address, they have an address.  They are 
part of the Z object.

> Reference is like a pointer to set up memory address.  The y in Z
> class is always bound to Y class and it can’t be unbound unless you
> change from reference to pointer.
>
> struct X
> {
> 	X( int _x, int _y ) : x( _x ), y( _y )
> 	{
> 	}
>
> 	~X()
> 	{
> 	}
>
> 	int x;
> 	int y;
> };
>
> struct Y
> {
> 	Y( X&  _x ) : x( _x )
> 	{
> 	}
>
> 	~Y()
> 	{
> 	}
>
> 	X&x; // reference
> };
>
> struct Z
> {
> 	Z( int a, int b ) : x( a, b ), y( x ) // initialized y( x )
> 	{
> 	}
>
> 	~Z()
> 	{
> 	}
>
> 	X x;
> 	Y y;
> };
>
>
> int main()
> {
> 	Z z( 1, 2 );
>
> 	return 0;
>
> }


-- 
Ian Collins

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