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Interesting const behavior

Started by daerid May 24, 2003 at 12:43 PM 3 replies 300+ views

Original Post

May 24, 2003 at 12:43 PM

  
struct test
{
	test( int& ref ) : i( ref ) {}

	int& i;
};

int main( int argc, char** argv ) {
	
	int i = 0;
	test t( i );

	const test& tr = t;

	tr.i = 4;

	return 0;
}

Why does that compile and work? I was under the impression that when an object/reference is defined as const, it''s members are treated as const (i.e: the int& i in struct test would be treated as const int& i). I''d like to understand this, if anybody''s got a reference from the standard that explains it, I''d be most appreciative. Thanks

JohnBolton

132

JohnBolton

May 25, 2003 at 3:33 AM

quote:
Original post by daerid
...
I was under the impression that when an object/reference is defined as const, it''s members are treated as const...

Yes, but tr.i is a reference to a non-const. You can''t change tr, and you can''t change test::i, but you can change the value that tr.i references.

Effectively,

tr.i = 4;

is the same as

i = 4;

daerid

Author

daerid

May 25, 2003 at 6:47 AM

Huh... ok. That clears it up. Thanks a lot guys

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