Item 7: declare Destructors (destructor) as virtual in polymorphic base classes (polymorphism base class)
By Scott Meyers
Translator: fatalerror99 (itepub's nirvana)
Release: http://blog.csdn.net/fatalerror99/
There are many ways to get the time, so it is necessary to establish a timekeeper base class (base class), and
Multiple inheritance and virtual base classes, multiple inheritance base classesMultiple inheritance of implicit classes describes classes with multiple direct base classes. Multi-inheritance brings two main problems:① Inherit the same name method from two different base classes;② Inherit multiple instances of the same
1, why the size of the class is not allowed in C + + is 0Class Zerosizet {}; Zerosizet Z[10];z[i]-z[j]; is usually obtained by dividing the number of bytes between two addresses by the type size, while the type size is 0 will be problematic2, why sometimes more than one class composition instance occupies the same spaceClass empty{};class emptytoo:public empty{};class emptythree:public emptytoo{};sizeof (Empty): 1sizeof (EmptyToo): 1sizeof (emptythree): 1Empty
C + + Primer Learning Note _31_ Object-oriented Programming (2)-Inheritance (ii): Inheritance and constructors, conversions from derived classes to base classes, base classes to derived classesa member function that cannot be automatically inheritedconstructor functionCopy constructorDestructors= operatorsecond, inheritance and constructor function The constructors of the
This article mainly introduces the usage of the HTML base tag, as well as the analysis of the role of the HTML base tag, let's take a look at this article.
First, let's analyze the role of the HTML base tag:
The base tag is the base URL tag in the HTML language, which is a
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Msgsender is known to be specially crafted for companyz. Next, consider derived class (derived class) loggingmsgsender:
Template Class loggingmsgsender: Public msgsender Public:...Void sendclearmsg (const msginfo info){Write "before sending" info to the log;
Sendclear (Info );// If Company = companyz,// This function doesn' t exist!Write "after sending" info to the log;}...
};
As written in comments, when the bas
Google base is not just eBay! Exciting Google BaseWhen I saw the base on Google code, I searched for the relevant information. The Chinese language basically described him as an opponent of eBay.So I posted the following materials here to make more people realize the great significance of Google base.
Google base is
How to obtain the correct base estimation and base EstimationOriginal article: http://www.oracle.com/technetwork/issue-archive/2013/13-jan/o13asktom-1886639.htmlI have a question about joining with collections and cardinality estimation. the optimizer is always estimating that 8,168 rows are coming back from my collection, and because of that, it is using inefficient plans. the estimate of 8,168 is more tha
Very detailed! Reprint LinkConversion of C + + base classes to derived classesIn public inheritance, private inheritance, and protection inheritance, only public inheritance preserves the characteristics of the base class well, preserving all members of the base class except constructors and destructors, and the access rights of the public or protected members of
The simple base station positioning program describes how to obtain the current base station location in detail. The following is a brief summary:
In the Android operating system, base station positioning is actually very simple. let's first talk about the implementation process:
Call the API (telephonymanager) in the SDK to obtain information such as MCC, MNC,
I finally figured out the problem, why didn't the Cellid of the WCDMA base station obtained by Google map mobile edition, MobileTrack, and FieldTest of network optimization be the CellTrack91 or the number in the base station table... This problem is very difficult to say. I have known it before, but I have never studied it in depth, because it does not affect my use. But I was bored lying in bed before I w
Analysis of base tag usage instances and base instance analysis in JSP page files
This document analyzes the usage of the base tag in the JSP page file. We will share this with you for your reference. The details are as follows:
When we use IDE tools to generate JSP pages, we usually include the following two pieces of code,
They are definitely not useless code,
Zend Framework Tutorial Action of the base class Zend_controller_action detailed, Controller base class
This article describes the base class zend_controller_action for the action of the Zend Framework tutorial. Share to everyone for your reference, as follows:
The realization of zend_controller_action
The Zend framework's action controller needs to inherit zend
Signalsitemap is a base station information software specially designed for communication practitioners and communication enthusiasts.
Supports gnetwork, cnetwork, and W networks, without the need for local databases to automatically label the current service base station, and supports database tagging for personalized information.
Displays the location, signal strength, distance between you and the
Algorithm --- bucket sorting and base sorting, algorithm --- bucket Base
Bucket sorting is no longer a comparison-based sorting method. It is a clever sorting method, but this sorting method requires that the sequence to be sorted meet the following two features:
All values of the columns to be sorted are in an enumerated range;
The enumerated range of the column to be sorted should not be too large; otherw
With the emergence of a large number of Wi-Fi hotspots and micro-cell base stations, the era of a single large base station tower may end at this year's World Mobile Communication Conference. This year's World Mobile Communication Conference will show a variety of small base stations and Wi-Fi integrated systems.
Ip. access is one of the Infrastructure vendors in
the network connection needs to detect the network situation, assuming that the network condition is faulty, a popup dialog box to remind users to set up the network or check.Like this, we'd better have a separate approach, so we don't have to write a lot of code to set up in every activity.But because we are directly integrated from the finalactivity, so a solution is to directly change our finalactivity source code, add these public methods. However, this changes the external framework of the
"Topic link"http://www.lydsy.com/JudgeOnline/problem.php?id=1835Test instructionsThere are n villages, each of which is located in D[i], which requires the establishment of no more than K base stations, the cost of building a base station in village I is c[i], if there is a base station within the village I not more than S[i], the village is covered, village I is
The base class baseoutput explicitly inherits an interface ioutput, and the class trackoutput inherits baseoutput, and also inherits the ioutput interface. Assume that ioutput has a method output, so there are two output methods in trackoutput, one source is the base class baseoutput and the other source is the interface ioutput. This leads to confusion. What should I do? Let's take a look at the following
The last time I provided a code response,
Since C ++ stand (C ++ Standards Committee) does not specify specific implementation methods, each compiler vendor may adopt different implementation methods,
The methods used in different ages may be different, and different results may be obtained. Here, I use vc7.1 as a debugging tool
Deeply analyzes the memory layout in the C ++ virtual inheritance step by step;
This section starts with empty virtual base
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