C++ 默认初始化会将数组元素设置为其默认值吗？

Question

考虑以下代码：

#include <iostream>

using namespace std;

int main(){
  int* p = new int[2];
  for (int i = 0; i < 2; i++)
    cout << p[i] << endl;  
  return 0;
}

我运行它好几次了。它总是产生以下输出：

0
0

我可以假设 C++ 默认初始化将数组元素设置为其默认值吗？在这种情况下，我可以假设 p 的元素值始终设置为 0 吗？

我已阅读以下相关问题。但他们并没有专门针对我的情况：

How to initialise memory with new operator in C++?
Operator new initializes memory to zero

Answer 1

Can I assume that C++ default-initialization set array elements to its default value?

否，因为 default initialization:

if T is an array type, every element of the array is default-initialized;

且元素类型为int，则

otherwise, nothing is done: the objects with automatic storage duration (and their subobjects) are initialized to indeterminate values.

另一方面，list initialization(since C++11) like int* p = new int[2]{}; or int* p = new int[2]{0};, or value initialization 像 int* p = new int[2](); 将保证，对于 int 所有元素都将被零初始化。

C++ 默认初始化会将数组元素设置为其默认值吗？

Will C++ default-initialization set array elements to its default value?

c++

arrays

initialization

new-operator