Re: Enum plus std::vector questions

From:
"Jack" <jl@knight.com>
Newsgroups:
microsoft.public.vc.language
Date:
Sun, 15 Jul 2007 19:26:11 +0800
Message-ID:
<usw8lJtxHHA.140@TK2MSFTNGP02.phx.gbl>
"Heinz Ozwirk" <SPAMhozwirk@arcor.de> ???g???l???s?D:4699feda$0$3842$9b4e6d93@newsspool4.arcor-online.net...

"Jack" <jl@knight.com> schrieb im Newsbeitrag
news:ORFnvusxHHA.2432@TK2MSFTNGP04.phx.gbl...

Question 1:
I use enum in my application
enum {
  APPLE = 1,
  ORANGE,
  PEAR,
  WATER_MELON
};

When I probe a variable of say APPLE, it just shows '1' rather than
'APPLE'... how do i fix that?


Write a function that accepts one of your enumeration values und displays
the appropriate text.

Is it possible to do somethin' like this?
pPtr->item = (byte) item;
When I probe this, I get APPLE on the tool tip if the item is 1?
Could I just cast item (originally byte) to the name of the enum?
say
pPtr->item = (fruit) item
so that making pPtr->item to display APPLE on the tool tip?
Thanks
Jack

Question 2:
if I have a std::vector<FRUIT> fruitarr; ,
When I want to add a new item, do I just do a or b? Or both of them are
just fine

a) memcpy (fruitarr[count], fruit, sizeof(fruit));
b) or fruitarr[count] = fruit;


None of them adds a new item. Both (if written correctly) would assign a
new value to an existing item. Use std::vector<>::push_back (or other
members of vector) to add new items.

Regarding memcpy -- avoid it whenever possible. If assignment works, as it
does above, use it. If it doesn't -- think why it doesn't, and think twice
before you try to use memcpy as a last resort. Remember, memcpy does not
know about user defined assignment operators, copy cobstructors, v-tables
or other C++ stuff.

Also, in your example, memcpy will not work, at least not as written in
line b. memcpy uses pointers, and at least fruitarr[count] is not a
pointer.

   Heinz

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