Constructor and destructor -- Initialization & Cleanup in C++
Why need initialization and cleanup?
A large segment of C bugs occur when the programmer forgets to initialize or clean up a variable.
The class designer can guarantee initialization of every object by providing a special function called the constructor. If a class has a constructor, the compiler automatically calls that constructor at the point an object is created, before client programmers can get their hands on the object. The constrctor call isnot even an option for the client programmer, it is performed by the compiler at the point the object is defined.
Default constructors
a default constructor is ont that can be called with no arguments. A default constructor is used to create a "vanilla object". The default constructor is so important that if and only if there are no constructors for a structure(struct or class), the compiler will automatically create one for you.
For example
class V{
int i;
};
void main()
{
V v, v2[10];
}
It is OK.
But if any constructors are defined, however, and there's no default constructor, the instances of V above will generate compile-time errors.
Constructor and destructor -- Initialization & Cleanup in C++的更多相关文章
- Constructor Acquires, Destructor Releases Resource Acquisition Is Initialization
w https://zh.wikipedia.org/wiki/RAII RAII要求,资源的有效期与持有资源的对象的生命期严格绑定,即由对象的构造函数完成资源的分配(获取),同时由析构函数完成资源的 ...
- __attribute__中constructor和destructor
1.前言 最近看到一份代码,看到一个函数前面用__attribute__((destructor))修饰,当时感觉有点怪怪的,搜了整个程序,也没发现哪个地方调用这个函数.于是从字面意思猜想,该函数会在 ...
- TIJ——Chapter Five:Initialization & Cleanup
Method overloading |_Distinguishing overloaded methods If the methods hava the same name, how can Ja ...
- Thinking in Java,Fourth Edition(Java 编程思想,第四版)学习笔记(六)之Initialization & Cleanup
Two of these safety issues are initialization and cleanup. initialization -> bug cleanup -> ru ...
- __attribute__中constructor和destructor[总结]
1.前言 最近看到一份代码,看到一个函数前面用__attribute__((destructor))修饰,当时感觉有点怪怪的,搜了整个程序,也没发现哪个地方调用这个函数.于是从字面意思猜想,该函数会在 ...
- C++ Knowledge series Conversion & Constructor & Destructor
Everything has its lifecycle, from being created to disappearing. Pass by reference instead of pass ...
- 构建器Constructor的返回值/构建器
构建器Constructor的返回值? 为什么会有这个问题? 在<Thinking in Java>中文Quanke翻译版本第四章初始化和清除,原书第五章Initialization&am ...
- Is it always safe to call getClass() within the subclass constructor?(转)
14down votefavorite An article on classloading states that the method getClass() should not be cal ...
- C++ 类 复制构造函数 The Copy Constructor
一.复制构造函数的定义 复制构造函数是一种特殊的构造函数,具有一般构造函数的所有特性.复制构造函数创建一个新的对象,作为另一个对象的拷贝.复制构造函数只含有一个形参,而且其形参为本类对象的引用.复制构 ...
随机推荐
- Android SlidingMenu 滑出侧边栏
最近有个项目需要使用侧边栏,而且希望是左右两侧都能够滑出侧边菜单,在网上查找实现方式时,发现大家用的最多的还是大神jfeinstein10的SlidingMenu库,地址https://github. ...
- Python Requests库
背景 Requests is an elegant and simple HTTP library for Python, built for human beings. Requests是一个优雅简 ...
- 升级cocoapods到1.2 beta版本的方法
最近写Swfit3.0, 要用到一些框架, 然后就用cocoapods嘛, 结果说要cocoapods1.1.0版本才行, 而自己的是cocoapods1.0.1版本的, 所以就想着升级嘛, 结果就遇 ...
- 配置nginx如果获取不到图片 去另外一台服务器获取
配置nginx服务器从一台服务器如果获取不到图片 从另外一台服务器中获取 location ^~ /uploads/ { root /data/weiwend/weiwang; try_files $ ...
- Apache Shiro 集成-Cas
http://blog.csdn.net/peterwanghao/article/details/8825008 Shiro集成CAS是在1.2版本里新增的功能. Shiro-cas模块将应用作为C ...
- 【转】国内较快的maven镜像
国内连接maven官方的仓库更新依赖库,网速一般很慢,收集一些国内快速的maven仓库镜像以备用. ====================国内OSChina提供的镜像,非常不错=========== ...
- 在XMPP的JAVA开源实现Openfire中,增加LBS 附近的人功能
1. XMPP协议 与 Openfire XMPP协议是IM领域的标准协议了,具体可参考 http://xmpp.org 及RFC6120,RFC6121,RFC6122等相关文档. http: ...
- [Usaco2006 Nov]Corn Fields牧场的安排 壮压DP
看到第一眼就发觉是壮压DP 然后就三进制枚举子集吧. 这题真是壮压入门好题... 对于dp[i][j] 表示第i行,j状态下前i行的分配方案数. 那么dp[i][j]肯定是从i-1行转过来的 那么由于 ...
- LVM物理卷命令
1. 物理卷命令 一般维护命令: #pvscan //在系统的全部磁盘中搜索已存在的物理卷 #pvdisplay 物理卷全路径名称 //用于显示指定物理卷的属性. #pvdata 物理卷全路径名 ...
- windows 下rabbitmq 安装---转载
原文地址:http://blog.sina.com.cn/s/blog_7cc0c8cc0101mb4a.html 1.下载并安装erlang,http://www.erlang.org/downlo ...