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by: Dave |
last post by:
Hello all,
After perusing the Standard, I believe it is true to say that once you
insert an element into a std::list<>, its location in memory never changes.
This makes a std::list<> ideal for storing vertices of an arbitrary n-ary
tree where a vertex contain pointers to its parent / children. These parent
/ child vertices need to stay put if we've got pointers to them somewhere!
Am I correct in my assertion?
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by: matty.hall |
last post by:
I have two classes: a base class (BaseClass) and a class deriving from
it (DerivedClass). I have a List<DerivedClass> that for various
reasons needs to be of that type, and not a List<BaseClass>. However, I
need to cast that list to a List<BaseClass> and it is not working. The
code is below. I get the following exception:
"Unable to cast object of type 'System.Collections.Generic.List`1' to
type 'System.Collections.Generic.List`1'."
...
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by: Paul |
last post by:
Hi,
I feel I'm going around circles on this one and would appreciate some other
points of view.
From a design / encapsulation point of view, what's the best practise for
returning a private List<as a property.
Consider the example below, the class "ListTest" contains a private "List<>"
called "strings" - it also provides a public method to add to that list,
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by: Andrew Robinson |
last post by:
I have a method that needs to return either a Dictionary<k,vor a List<v>
depending on input parameters and options to the method.
1. Is there any way to convert from a dictionary to a list without
itterating through the entire collection and building up a list?
2. is there a common base class, collection or interface that can contain
either/both of these collection types and then how do you convert or cast
from the base to either a...
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by: Zytan |
last post by:
Obviously you can't just use a simple for loop, since you may skip
over elements.
You could modify the loop counter each time an element is deleted.
But, the loop ending condition must be checked on each iteration,
since the Count changes as you delete elements. I would think it is
guaranteed to be computed each time, and not cached.
So, is this the best way?
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by: Zytan |
last post by:
This returns the following error:
"Cannot modify the return value of
'System.Collections.Generic.List<MyStruct>.this' because it is
not a variable"
and I have no idea why! Do lists return copies of their elements?
Why can't I change the element itself?
class Program
{
private struct MyStruct
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by: Lee Crabtree |
last post by:
This seems inconsistent and more than a little bizarre.
Array.Clear sets all elements of the array to their default values (0,
null, whatever), whereas List<>.Clear removes all items from the list.
That part makes a reasonable amount of sense, as you can't actually take
items away from an Array. However, there doesn't seem to be a way to
perform the same operation in one fell swoop on a List<>.
For example:
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by: A |
last post by:
Hi,
I don't get this method... Could someone please explain it?
I have a number generator where I want to add the numbers to a List<long>.
Before I add each number, I want to make sure that the number does not
already exist. Sample code:
List<longnumlist = new List<long>();
long newNumber = generator.New(); // generates the new number
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by: Ben Pfaff |
last post by:
The C++ standard says in 23.2.2.4 "list operations" that the
various forms of splice invalidate iterators and references to
the spliced elements. This makes the splice operation a lot less
useful than it otherwise could be. It seems unnecessary to
invalidate these iterators and references, and I am puzzled why
the standard says that it happens. Furthermore, the "merge"
operation that also moves elements from one list to another does...
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by: =?Utf-8?B?UGhpbA==?= |
last post by:
I have seen the samples for Find that explain how to use the predicate, but
they are always searching for a pre-defined value. What I don't understand
is how to search for a random value stored in a variable.
For example,
List<intitems;
int val=3;
items.Add(1);
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by: Hystou |
last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it.
First, let's disable language synchronization. With a Microsoft account, language settings sync across devices. To prevent any complications,...
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by: Oralloy |
last post by:
Hello folks,
I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>".
The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed.
This is as boiled down as I can make it.
Here is my compilation command:
g++-12 -std=c++20 -Wnarrowing bit_field.cpp
Here is the code in...
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by: jinu1996 |
last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth.
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by: Hystou |
last post by:
Overview:
Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...
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by: tracyyun |
last post by:
Dear forum friends,
With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each protocol has its own unique characteristics and advantages, but as a user who is planning to build a smart home system, I am a bit confused by the choice of these technologies. I'm particularly interested in Zigbee because I've heard it does some...
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by: conductexam |
last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one.
At the time of converting from word file to html my equations which are in the word document file was convert into image.
Globals.ThisAddIn.Application.ActiveDocument.Select();...
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by: TSSRALBI |
last post by:
Hello
I'm a network technician in training and I need your help.
I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs.
The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols.
I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
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by: muto222 |
last post by:
How can i add a mobile payment intergratation into php mysql website.
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by: bsmnconsultancy |
last post by:
In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating effective websites that not only look great but also perform exceptionally well. In this comprehensive...
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