soft and program: comp.lang.c++ - 26 new messages in 15 topics

comp.lang.c++
http://groups.google.com/group/comp.lang.c++?hl=en

comp.lang.c++@googlegroups.com

Today's topics:

* Return value of functor object in for_each algorithm - 1 messages, 1 author
http://groups.google.com/group/comp.lang.c++/t/684394bf92375bf6?hl=en
* GNU C++ Profiling under Linux - 2 messages, 2 authors
http://groups.google.com/group/comp.lang.c++/t/ac18eab174350eac?hl=en
* static array declaration in flyweight pattern - 2 messages, 1 author
http://groups.google.com/group/comp.lang.c++/t/b4df4db8ab107e11?hl=en
* const across multiplely linked files - 1 messages, 1 author
http://groups.google.com/group/comp.lang.c++/t/0502a7a5e7c946f9?hl=en
* Wholesale chanel handbags,prada handbags,fendi handbags,coach handbags,louis
vuitton handbags,gucci handbags and wallets,paypal payement - 2 messages, 1
author
http://groups.google.com/group/comp.lang.c++/t/099e2337fc1f8ac4?hl=en
* <www.shoesspring.com> New louis vuitton real leather shoes,gucci handbags on
sale,paypal payment - 1 messages, 1 author
http://groups.google.com/group/comp.lang.c++/t/a8072e661a7fcd38?hl=en
* C++ way to convert ASCII digits to Integer? - 3 messages, 2 authors
http://groups.google.com/group/comp.lang.c++/t/c6620161a9dfea0b?hl=en
* the last element in a container, (std::vector, std:map ... ) - 3 messages, 2
authors
http://groups.google.com/group/comp.lang.c++/t/cd0fbe9e1f01bdb9?hl=en
* vector stl destruct - 5 messages, 3 authors
http://groups.google.com/group/comp.lang.c++/t/9675399059078ffb?hl=en
* >>>Paypal Payment- China Wholesaler Fashion Brand Handbags CUCCI.LV.ED Hardy.
..<<<-www.guomeitrade.com - 1 messages, 1 author
http://groups.google.com/group/comp.lang.c++/t/dd79425e35025de2?hl=en
* Discount LV sunglasses Louis Vuitton Handbag clothes at : www.topsellingnow.
com - 1 messages, 1 author
http://groups.google.com/group/comp.lang.c++/t/cf440fe9b484464d?hl=en
* Wholesale nike shox NZ ( www.topsellingnow.com ) Wholesale nike shox R4,
Wholesale Nike Dunk SB sneakers - 1 messages, 1 author
http://groups.google.com/group/comp.lang.c++/t/4389b8d240d28be6?hl=en
* china nike shox r3 r4 nike shox nz nike shox oz new styles models nike (www.
topsellingnow.com) wholesale sneakers jordan sneakers at factory wholesale - 1
messages, 1 author
http://groups.google.com/group/comp.lang.c++/t/c32942732844ffbb?hl=en
* discount hoody,A&F hot clothes,artful dodger hoody china online shop www.
topsellingnow.com - 1 messages, 1 author
http://groups.google.com/group/comp.lang.c++/t/a5fd9e1f4dba919e?hl=en
* (www.topsellingnow.com) sell ed hardy t-shirts hoodies,sell Newest authentic
NFL,NBA,MLB jerseys with tags - 1 messages, 1 author
http://groups.google.com/group/comp.lang.c++/t/caf1f297aa2c6120?hl=en

==============================================================================
TOPIC: Return value of functor object in for_each algorithm
http://groups.google.com/group/comp.lang.c++/t/684394bf92375bf6?hl=en
==============================================================================

== 1 of 1 ==
Date: Sun, May 31 2009 6:17 am
From: Jerry Coffin

In article <5602b353-1abd-411d-965b-
af68c9fdcc6d@s21g2000vbb.googlegroups.com>, james.kanze@gmail.com
says...

[ ... ]

> In general, it's best to make all copies of functional objects
> idempotent, using an additional level of indirection if
> necessary. For functional objects with mutable state, there are
> two more or less standard solutions:
>
> -- The client defines an instance of the state, and passes an
> address of it to the constructor of the functional object,
> which contains a pointer to it. This is the simplest and
> most efficient solution; if there is mutable state which the
> client doesn't need to know about, however, it breaks
> encapsulation.
>
> -- The functional object defines a nested class type with
> state. The non-copy constructors allocate an instance of
> the state dynamically, and the functional object uses
> reference counting (boost::shared_ptr works fine here,
> although other reference counted pointers may be more
> efficient) so that copies share the instance of the state.

Option C: Consider using std::accumulate instead of std::for_each. Most
times that people want to maintain state across invocations, they're
accumulating something in their functor, and they'd be better off using
std::accumulate to do the job.

--
Later,
Jerry.

The universe is a figment of its own imagination.

==============================================================================
TOPIC: GNU C++ Profiling under Linux
http://groups.google.com/group/comp.lang.c++/t/ac18eab174350eac?hl=en
==============================================================================

== 1 of 2 ==
Date: Sun, May 31 2009 6:24 am
From: Rolf Magnus

Markus Raab wrote:

> Ignoramus17844 wrote:
>
>> Is there something like that for Linux?
>
> Have you tried valgrind?

If the performance with gprof is an issue, valgrind isn't really an
alternative.

== 2 of 2 ==
Date: Sun, May 31 2009 7:04 am
From: Andrew Tomazos

On May 29, 4:13 pm, Ignoramus17844 <ignoramus17...@NOSPAM.
17844.invalid> wrote:
> I wanted to see if I can find a profiler that would stop my
> app once in a while, examine stack, and continue to run immediately
> after taking a call stack snapshot.

It may be easier than you think to roll your own programmatically by
setting up an asynchronous periodic signal interrupt, and within the
signal handler calling the glibc 'backtrace' call.

In the glibc manual see "Signal Handling" and "Backtraces":

http://www.gnu.org/s/libc/manual/html_node/Signal-Handling.html
http://www.gnu.org/s/libc/manual/html_node/Backtraces.html

Enjoy,
Andrew.

--
Andrew Tomazos <andrew@tomazos.com> <http://www.tomazos.com>

==============================================================================
TOPIC: static array declaration in flyweight pattern
http://groups.google.com/group/comp.lang.c++/t/b4df4db8ab107e11?hl=en
==============================================================================

== 1 of 2 ==
Date: Sun, May 31 2009 6:34 am
From: pauldepstein@att.net

I'm concerned about this code which I saw from sourcemaking.com pasted
below. In particular, I question the line -- Icon
*FlyweightFactory::_icons[]; I have marked this line out below by //
************* so that those interested can easily find it in
context. My question is quite simple, and only a tiny fraction of the
pasted code is probably relevant. (But I provided full context just
in case.)

The line Icon *FlyweightFactory::_icons[]; seems a strange definition
of an array. In the class Icon, this array is declared as having
dimension 5 but the definition doesn't specify the size.
The definition of the array also appears to be uninitialized. In
particular, I would be interested to know if the static array
declaration ensures that all the int-pointer members of the array are
null pointers. They are either null pointers or uninitialized
pointers but which?

I would probably have written Icon *FlyweightFactory::_icons[] = {0,
0, 0, 0, 0};

but it's possible that the code does this anyway. Do the int-pointers
initialize to 0 anyway even if this is not made explicit as I did?

Thanks very much for your help.

Paul Epstein

#include <iostream.h>
#include <string.h>

class Icon
{
public:
Icon(char *fileName)
{
strcpy(_name, fileName);
if (!strcmp(fileName, "go"))
{
_width = 20;
_height = 20;
}
if (!strcmp(fileName, "stop"))
{
_width = 40;
_height = 40;
}
if (!strcmp(fileName, "select"))
{
_width = 60;
_height = 60;
}
if (!strcmp(fileName, "undo"))
{
_width = 30;
_height = 30;
}
}
const char *getName()
{
return _name;
}
draw(int x, int y)
{
cout << " drawing " << _name << ": upper left (" << x << ","
<< y <<
") - lower right (" << x + _width << "," << y + _height <<
")" <<
endl;
}
private:
char _name[20];
int _width;
int _height;
};

class FlyweightFactory
{
public:
static Icon *getIcon(char *name)
{
for (int i = 0; i < _numIcons; i++)
if (!strcmp(name, _icons[i]->getName()))
return _icons[i];
_icons[_numIcons] = new Icon(name);
return _icons[_numIcons++];
}
static void reportTheIcons()
{
cout << "Active Flyweights: ";
for (int i = 0; i < _numIcons; i++)
cout << _icons[i]->getName() << " ";
cout << endl;
}
private:
enum
{
MAX_ICONS = 5
};
static int _numIcons;
static Icon *_icons[MAX_ICONS];
};

int FlyweightFactory::_numIcons = 0;
Icon *FlyweightFactory::_icons[]; //
**********************************************************************************

class DialogBox
{
public:
DialogBox(int x, int y, int incr): _iconsOriginX(x), _iconsOriginY
(y),
_iconsXIncrement(incr){}
virtual void draw() = 0;
protected:
Icon *_icons[3];
int _iconsOriginX;
int _iconsOriginY;
int _iconsXIncrement;
};

class FileSelection: public DialogBox
{
public:
FileSelection(Icon *first, Icon *second, Icon *third): DialogBox
(100, 100,
100)
{
_icons[0] = first;
_icons[1] = second;
_icons[2] = third;
}
void draw()
{
cout << "drawing FileSelection:" << endl;
for (int i = 0; i < 3; i++)
_icons[i]->draw(_iconsOriginX + (i *_iconsXIncrement),
_iconsOriginY);
}
};

class CommitTransaction: public DialogBox
{
public:
CommitTransaction(Icon *first, Icon *second, Icon *third):
DialogBox(150,
150, 150)
{
_icons[0] = first;
_icons[1] = second;
_icons[2] = third;
}
void draw()
{
cout << "drawing CommitTransaction:" << endl;
for (int i = 0; i < 3; i++)
_icons[i]->draw(_iconsOriginX + (i *_iconsXIncrement),
_iconsOriginY);
}
};

int main()
{
DialogBox *dialogs[2];
dialogs[0] = new FileSelection(FlyweightFactory::getIcon("go"),
FlyweightFactory::getIcon("stop"), FlyweightFactory::getIcon
("select"));
dialogs[1] = new CommitTransaction(FlyweightFactory::getIcon
("select"),
FlyweightFactory::getIcon("stop"), FlyweightFactory::getIcon
("undo"));

for (int i = 0; i < 2; i++)
dialogs[i]->draw();

FlyweightFactory::reportTheIcons();
}

== 2 of 2 ==
Date: Sun, May 31 2009 6:43 am
From: pauldepstein@att.net

On May 31, 3:34 pm, pauldepst...@att.net wrote:
> I'm concerned about this code which I saw from sourcemaking.com pasted
> below. In particular, I question the line -- Icon
> *FlyweightFactory::_icons[]; I have marked this line out below by //
> ************* so that those interested can easily find it in
> context. My question is quite simple, and only a tiny fraction of the
> pasted code is probably relevant. (But I provided full context just
> in case.)
>
> The line Icon *FlyweightFactory::_icons[]; seems a strange definition
> of an array. In the class Icon, this array is declared as having
> dimension 5 but the definition doesn't specify the size.
> The definition of the array also appears to be uninitialized. In
> particular, I would be interested to know if the static array
> declaration ensures that all the int-pointer members of the array are
> null pointers. They are either null pointers or uninitialized
> pointers but which?
>
> I would probably have written Icon *FlyweightFactory::_icons[] = {0,
> 0, 0, 0, 0};
>
> but it's possible that the code does this anyway. Do the int-pointers
> initialize to 0 anyway even if this is not made explicit as I did?
>
> Thanks very much for your help.
>
> Paul Epstein
>
> #include <iostream.h>
> #include <string.h>
>
> class Icon
> {
> public:
> Icon(char *fileName)
> {
> strcpy(_name, fileName);
> if (!strcmp(fileName, "go"))
> {
> _width = 20;
> _height = 20;
> }
> if (!strcmp(fileName, "stop"))
> {
> _width = 40;
> _height = 40;
> }
> if (!strcmp(fileName, "select"))
> {
> _width = 60;
> _height = 60;
> }
> if (!strcmp(fileName, "undo"))
> {
> _width = 30;
> _height = 30;
> }
> }
> const char *getName()
> {
> return _name;
> }
> draw(int x, int y)
> {
> cout << " drawing " << _name << ": upper left (" << x << ","
> << y <<
> ") - lower right (" << x + _width << "," << y + _height <<
> ")" <<
> endl;
> }
> private:
> char _name[20];
> int _width;
> int _height;
>
> };
>
> class FlyweightFactory
> {
> public:
> static Icon *getIcon(char *name)
> {
> for (int i = 0; i < _numIcons; i++)
> if (!strcmp(name, _icons[i]->getName()))
> return _icons[i];
> _icons[_numIcons] = new Icon(name);
> return _icons[_numIcons++];
> }
> static void reportTheIcons()
> {
> cout << "Active Flyweights: ";
> for (int i = 0; i < _numIcons; i++)
> cout << _icons[i]->getName() << " ";
> cout << endl;
> }
> private:
> enum
> {
> MAX_ICONS = 5
> };
> static int _numIcons;
> static Icon *_icons[MAX_ICONS];
>
> };
>
> int FlyweightFactory::_numIcons = 0;
> Icon *FlyweightFactory::_icons[]; //
> **********************************************************************************
>
> class DialogBox
> {
> public:
> DialogBox(int x, int y, int incr): _iconsOriginX(x), _iconsOriginY
> (y),
> _iconsXIncrement(incr){}
> virtual void draw() = 0;
> protected:
> Icon *_icons[3];
> int _iconsOriginX;
> int _iconsOriginY;
> int _iconsXIncrement;
>
> };
>
> class FileSelection: public DialogBox
> {
> public:
> FileSelection(Icon *first, Icon *second, Icon *third): DialogBox
> (100, 100,
> 100)
> {
> _icons[0] = first;
> _icons[1] = second;
> _icons[2] = third;
> }
> void draw()
> {
> cout << "drawing FileSelection:" << endl;
> for (int i = 0; i < 3; i++)
> _icons[i]->draw(_iconsOriginX + (i *_iconsXIncrement),
> _iconsOriginY);
> }
>
> };
>
> class CommitTransaction: public DialogBox
> {
> public:
> CommitTransaction(Icon *first, Icon *second, Icon *third):
> DialogBox(150,
> 150, 150)
> {
> _icons[0] = first;
> _icons[1] = second;
> _icons[2] = third;
> }
> void draw()
> {
> cout << "drawing CommitTransaction:" << endl;
> for (int i = 0; i < 3; i++)
> _icons[i]->draw(_iconsOriginX + (i *_iconsXIncrement),
> _iconsOriginY);
> }
>
> };
>
> int main()
> {
> DialogBox *dialogs[2];
> dialogs[0] = new FileSelection(FlyweightFactory::getIcon("go"),
> FlyweightFactory::getIcon("stop"), FlyweightFactory::getIcon
> ("select"));
> dialogs[1] = new CommitTransaction(FlyweightFactory::getIcon
> ("select"),
> FlyweightFactory::getIcon("stop"), FlyweightFactory::getIcon
> ("undo"));
>
> for (int i = 0; i < 2; i++)
> dialogs[i]->draw();
>
> FlyweightFactory::reportTheIcons();
>
> }
>
>

Sorry, in the above, I said int-pointers. They are of course Icon-
pointers. So my question is whether these pointers are 0.

Thanks,

Paul Epstein

==============================================================================
TOPIC: const across multiplely linked files
http://groups.google.com/group/comp.lang.c++/t/0502a7a5e7c946f9?hl=en
==============================================================================

== 1 of 1 ==
Date: Sun, May 31 2009 6:53 am
From: SG

On 31 Mai, 13:23, "Aaron Gray" <ang.use...@gmail.com> wrote:
> I am trying to declare a const in a header file but have forgetten how.
>
> I have a class and I want a Null value for that struct to pass as an
> argument when it is not being used. Now it used to be done passing a '0',
> but the class now has an iheriting child class e.g. :-
>
> class A {...}
>
> fn( ..., A a, ...)

What's that supposed to be? A function declaration?

> and
>
> fn( ..., 0, ...)

And that? A function call expression? Or is this supposed to be an
overload?

> But now we have :-
>
> class B : public A {...}
>
> and fn(..., 0, ...) is declaring that parameter 2 is now ambiguous.

This all seems /very/ strange in terms of design. Why would you want
to pass an object that's part of an inheritance hierachy by value? Are
you sure that you don't misuse public inheritance and/or overloading
and/or pass-by-value?

> So what I wanted was to declare a 'NullA'.
>
> But it has to be declared in a header and there are multiple C++ files using
> the header and they all get linked to gether. So declaring in the header :-
>
> const NullA* = 0;
>
> is out.

Did you mean something like this?

A* const NullA = 0;

There's no problem with putting this definition inside a header that's
included in many files. This is a pointer constant and has internal
linkage.

> The only way I have found is :-
>
> class A {
> public:
> const Null;
> };
>
> then is one C++ file :-
>
> const A::Null = 0;

There's a lot wrong this this piece of code. C++ is statically typed
language. It doesn't let you declare variables without a type. Also,
you forgot to add "static" as a storage qualifier.

> [...]
> I am probably forgetting something very basic about C++.

Yes. You should brush up your C++ knowledge. C++ is not Java where a
declaration

void foo(A a) {...}

passes a reference to an object. There is no implied indirection in C+
+. If you want to pass objects by reference or by address you need to
declare it (&, *). Also, post more details about what you're trying to
do (not just how) including a bit of code without any "..."s.

Cheers!
SG

==============================================================================
TOPIC: Wholesale chanel handbags,prada handbags,fendi handbags,coach handbags,
louis vuitton handbags,gucci handbags and wallets,paypal payement
http://groups.google.com/group/comp.lang.c++/t/099e2337fc1f8ac4?hl=en
==============================================================================

== 1 of 2 ==
Date: Sun, May 31 2009 6:59 am
From: footwear world trade

cheap jordan sneakers (www.shoesspring.com)

GUCCI bags ( paypal payment)
LV bags D&G bags CLOTHES

COACH bags ( paypal payment ) (www.shoesspring.com)

JIMMY CHOO bags ( paypal payment ) (www.shoesspring.com)

JUICY bags LV bags (www.shoesspring.com)

PRADA bags ( paypal payment ) (www.shoesspring.com)

BAPE bags ED Handy bags AF bags ( paypal payment )
(www.shoesspring.com)

fashion jeans cheap wholesaler
(paypal payment)

denim jeanscheap wholesaler (paypal payment) (www.shoesspring.com)

men's jeans brand jeans cheap wholesaler (paypal payment)
(www.shoesspring.com)

women jeans' jeans cheap wholesaler (paypal payment)
(www.shoesspring.com)

branded jeans cheap wholesaler (paypal payment)
(www.shoesspring.com)

designer jeans men jeans cheap wholesaler (paypal payment)
(www.shoesspring.com)

blue jeans cheap wholesaler (paypal payment) (www.shoesspring.com)

Cotton Shirting Fashion Shirts Dress Shirts cheap wholesaler (paypal
payment)

Casual Shirts Brand Shirtscheap wholesaler (paypal payment)
(www.shoesspring.com)

Long Sleeve Shirt

== 2 of 2 ==
Date: Sun, May 31 2009 7:19 am
From: footwear world trade

juicy suit wholesale (www.shoesspring.com)

wholesale armani shirt (www.shoesspring.com)

buy nike shoes at wholesale cheap price (www.shoesspring.com)

wholesale discount nike air force one shoes (www.shoesspring.com)

cheapest nike air max90 shoes nike maxltd shoes (paypal payment)

cheap gucci sneakers,prada sneakers (paypal payment)
(www.shoesspring.com)