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月光杯:
问题解决了吗?
Exceptions in HDFS -
iostreamin:
神,好厉害,这是我找到的唯一可以ac的Java代码,厉害。
[leetcode] word ladder II -
standalone:
One answer I agree with:引用Whene ...
How many string objects are created? -
DiaoCow:
不错!,一开始对这些确实容易犯迷糊
erlang中的冒号 分号 和 句号 -
standalone:
Exception in thread "main& ...
one java interview question
A copy constructor is called whenever a new variable is created from an object. This happens in the following cases (but not in assignment). C++ calls a copy constructor to make a copy of an object in each of the above cases. If there is no copy constructor defined for the class, C++ uses the default copy constructor which copies each field, ie, makes ashallow copy. If the object has no pointers to dynamically allocated memory, a shallow copy is probably sufficient. Therefore the default copy constructor, default assignment operator, and default destructor are ok and you don't need to write your own. If you need a copy constructor, it's because you need something like a deep copy, or some other management of resources. Thus is is almost certain that you will need a destructor and override the assignment operator. The copy constructor takes a reference to a Here is an example of a copy constructor for the Point class, which doesn't really need one because the default copy constructor's action of copying fields would work fine, but it shows how it works. A copy constructor is used to initialize a newly declared variable from an existing variable. This makes a deep copy like assignment, but it is somewhat simpler: [Question: When is the base (parent) class copy constructor called? Is it like Java and the parent constructor is called at the beginning of each constructor? Does it have to be explicit?]When copies of objects are made
Person q("Mickey"); // constructor is used to build q.
Person r(p); // copy constructor is used to build r.
Person p = q; // copy constructor is used to initialize in declaration.
p = q; // Assignment operator, no constructor or copy constructor.
f(p); // copy constructor initializes formal value parameter.
Don't write a copy constructor if shallow copies are ok
If you need a copy constructor, you also need a destructor and
operator=
Copy constructor syntax
const
parameter. It is const
to guarantee that the copy constructor doesn't change it, and it is a reference because a value parameter would require making a copy, which would invoke the copy constructor, which would make a copy of its parameter, which would invoke the copy constructor, which ...//=== file Point.h =============================================
class Point {
public:
. . .
Point(const Point& p); // copy constructor
. . .
//=== file Point.cpp ==========================================
. . .
Point::Point(const Point& p) {
x = p.x;
y = p.y;
}
. . .
//=== file my_program.cpp ====================================
. . .
Point p; // calls default constructor
Point s = p; // calls copy constructor.
p = s; // assignment, not copy constructor.
Difference between copy constructor and assignment
Unaddressed issue
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std::map
2017-08-06 22:41 592std::map<char,int> my ... -
lost on Py_DECREF/INCREF when handling PyList_Append in Python C extension
2015-11-03 21:41 1023The main hint is in the docs, i ... -
An Example of Using std::tr1::bind
2014-03-10 16:49 1490#include <iostream> #i ... -
c++中的virtual inheritance
2014-01-27 10:20 772http://stackoverflow.com/questi ... -
Java的Generics和c++的Template到底有什么不同?
2012-12-27 16:21 3208先了解Java的Generics: 根据Java的文档,Jav ... -
Calculating Permutations and Job Interview Questions
2011-06-18 17:44 923http://www.bearcave.com/random_ ... -
字符串指针、字符数组的sizeof和strlen结果
2010-09-27 08:36 1434int main(){ char *p1=" ... -
code snippet
2010-09-27 08:31 894char temp[3]; char temp2[3]; ... -
虚继承
2010-09-26 09:03 938http://www.cppblog.com/franksun ... -
调整堆的算法
2010-09-25 10:34 1121Begin adjustHeap(A[], i) // He ... -
multiset usage as heap
2010-09-24 21:37 1419Middle number There is a seque ... -
虚函数表又是怎样实现的?
2010-09-20 22:01 1294每个含有虚函数的类 ... -
正整数分解算法
2010-09-19 16:56 4004问题:将以正整数n表 ... -
异或运算法则
2010-09-14 09:47 21581. a ^ b = b ^ a 2 ... -
常量字符串为什么位于静态存储区
2010-09-13 22:41 1220http://hi.baidu.com/%D0%C7%BB%F ... -
errno.h
2010-08-10 08:46 1482查看错误代码errno是调试程序的一个重要方法。当linuc ... -
How to use fallocate system call
2010-08-07 22:19 3408/* * fallocate - utility to u ... -
Test performance of allocating a zeroed file via various methods
2010-08-07 22:09 1084/* * Test performance of a ... -
how to reverse the word sequence in a sentence?
2010-07-06 22:01 1207For example, "Welcome ... -
c++ dynamic binding
2010-07-06 21:20 874Good tutorial about c++ dynamic ...
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