C++ std::vector 的复制构造函数如何操作？
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How does std::vector's copy constructor operate?
提问by chadb
How does a std::vector<std::string>initialize its self when the following code is invoked
std::vector<std::string>调用以下代码时如何初始化自身
std::vector<std::string> original;
std::vector<std::string> newVector = original;
It would seem as if the copy constructor would be invoked on std::vector<std::string> newduring newVector = original, but how are the std::string's brought over inside of the orginal? Are they copies or new std::string's? So is the memory in newVector[0]the same as original[0].
看起来好像复制构造函数会在std::vector<std::string> newduring上被调用newVector = original，但是std::string's是如何被引入到 中的orginal？他们是副本还是新std::string的？内存newVector[0]也是如此original[0]。
The reason I ask is say I do the following
我问的原因是说我做了以下事情
#include <vector>
#include <string>
using namespace std;
vector<string> globalVector;
void Initialize() {
globalVector.push_back("One");
globalVector.push_back("Two");
}
void DoStuff() {
vector<string> t = globalVector;
}
int main(void) {
Initialize();
DoStuff();
}
twill fall out of scope of DoStuff(on a non optimized build), but if it tis just filled with pointers to the std::string's in globalVector, might the destructor be called and the memory used in std::stringdeleted, there for making globalVector[0]filled with garbage std::string's after DoStuffis called?
t就会掉出来的范围DoStuff（在非优化的版本），但如果它t只是充满了指针指向std::string的中globalVector，可能会在析构函数被调用，并在使用的内存std::string中删除，也用于制作globalVector[0]堆满了垃圾std::string的后DoStuff是叫？
A nut shell, I am basically asking, when std::vector's copy constructor is called, how are the elements inside copied?
一个坚果壳，我基本上是在问，当std::vector调用 的复制构造函数时，里面的元素是如何复制的？
回答by Dark Falcon
std::vectorand most other standard library containers store elements by value. The elements are copied on insertion or when the container is copied. std::stringalso maintains its own copy of the data, as far as your usage of it is concerned.
std::vector和大多数其他标准库容器按值存储元素。在插入或复制容器时复制元素。std::string还维护自己的数据副本，就您对数据的使用而言。
