Skip to main content

Operator new

In C++, if you want to mimic malloc style behavior in
pure C++ way then write

Box *b = (Box *) operator new (sizeof (Box)); // statement 1

By this I mean the constructor of Box will not be invoked
as you expect with malloc. Note that this is NOT equivalent to

Box * b = new Box; // Statement 2

because doing that invokes the constructor.

Statment 1 is know as "operator new"!!
AND
Statment 2 is know as "new operator"!!

You have to match statement 1 by
operator delete(b); // does not invoke destructor
and statement 2 by
delete b; // invokes destructor

Comments

Anonymous said…
What a nice blog you have! You can be sure that I'll be coming back!

Check my golfing blog!
Anonymous said…
October 2005
Carnival of Diasporas - no Armenians Allowed Filed under: Armenia , Diaspora , Technology - Posted by Katy on October 1st A few weeks ago I posted a link to the Carnival of Diasporas .
Hey, you have a great blog here! I'm definitely going to bookmark you!

I have a winning ad copy site/blog. It pretty much covers winning ad copy related stuff.

Come and check it out if you get time :-)
Sensational blog. I took pleasure in the site and I
will go back! Surfing online for blogs like this one
is worth my time.
Come as you are and look at my faxless cash advance blog.
Astonshing blog. I relished in the site and you
know I will be going to it again! Surfing the internet
hepls me to find blogs that arfe just as good.
It may look like it was hard work, but my 1800contacts coupon blog was simple.
Captivate blog. I surf the web for blogs this
nature.The site are wonderful and will be returned to
again!
Look who checking out my 1800contacts coupon code blog?
dat-girl said…
Unusual blog. I liked the site its from so much I
have to visit it again! I surf the web for blogs like
yours in my spare time.
Want to see top notch work, peep my 1800contacts coupon codes blog site for the bomb work!
Nice blog. I seen the site and I adored the work,
that I want to visit it more each day! I like
searching for blogs that have the same content like
this one!
Please discover my 1800contacts web coupon code blog.
lightly-blended said…
Hype blog. And I admire your site and plan on
returning to it! When I web surf it always helps me to
find great blogs.
Hey why don't you peep my 1800contacts coupon code blog site.
Great blog. I'm always finding blog like yours. It
got my attention and I will go to the site again!
Please proceed to my 1800contacts web coupon code blog when you find the time.
Exciting blog. Your site was amazing and will be
back again! I never get tired of looking for blogs
just like this one.
Please come by and see my 1800contacts coupon codes blog.
Great blog. I'm always finding blog like yours. It
got my attention and I will go to the site again!
Look into my 1800contacts coupon blog.
die4-u said…
Excellent blog.  I go though the web in search of
blogs like this one. Its so good, that I plan on
returning to its site!
Go and click my coupon codes 1800contacts blog.
Great blog. I surf the web looking for blogs like
this. Your site was on point and will be back again!
My plastic surgery illinois blog, is something you need to peep out!
I surf the web looking for blogs like this one.
Your site was on point and will be back again! Awesome
blog.
I wish I was like you, but I'll go and peep your 1800contacts web coupon code blog.

Popular posts from this blog

Multi-dimensional arrays in C++11

What new can be said about multi-dimensional arrays in C++? As it turns out, quite a bit! With the advent of C++11, we get new standard library class std::array. We also get new language features, such as template aliases and variadic templates. So I'll talk about interesting ways in which they come together.

It all started with a simple question of how to define a multi-dimensional std::array. It is a great example of deceptively simple things. Are the following the two arrays identical except that one is native and the other one is std::array?

int native[3][4];
std::array<std::array<int, 3>, 4> arr;

No! They are not. In fact, arr is more like an int[4][3]. Note the difference in the array subscripts. The native array is an array of 3 elements where every element is itself an array of 4 integers. 3 rows and 4 columns. If you want a std::array with the same layout, what you really need is:

std::array<std::array<int, 4>, 3> arr;

That's quite annoying for two r…

Understanding Fold Expressions

C++17 has an interesting new feature called fold expressions. Fold expressions offer a compact syntax to apply a binary operation to the elements of a parameter pack. Here’s an example. template <typename... Args> auto addall(Args... args) { return (... + args); } addall(1,2,3,4,5); // returns 15. This particular example is a unary left fold. It's equivalent to ((((1+2)+3)+4)+5). It reduces/folds the parameter pack of integers into a single integer by applying the binary operator successively. It's unary because it does not explicitly specify an init (a.k.a. identity) argument. So, let add it. template <typename... Args> auto addall(Args... args) { return (0 + ... + args); } addall(1,2,3,4,5); // returns 15. This version of addall is a binary left fold. The init argument is 0 and it's redundant (in this case). That's because this fold expression is equivalent to (((((0+1)+2)+3)+4)+5). Explicit identity elements will come in handy a little la…

Folding Monadic Functions

In the previous two blog posts (Understanding Fold Expressions and Folding Functions) we looked at the basic usage of C++17 fold expressions and how simple functions can be folded to create a composite one. We’ll continue our stride and see how "embellished" functions may be composed in fold expressions.

First, let me define what I mean by embellished functions. Instead of just returning a simple value, these functions are going to return a generic container of the desired value. The choice of container is very broad but not arbitrary. There are some constraints on the container and once you select a generic container, all functions must return values of the same container. Let's begin with std::vector.
// Hide the allocator template argument of std::vector. // It causes problems and is irrelevant here. template <class T> struct Vector : std::vector<T> {}; struct Continent { }; struct Country { }; struct State { }; struct City { }; auto get_countries…