c++ - 默认构造一个整数数组会对其进行零初始化吗？

Question

如果我有一个包含数组成员的结构，并且我在结构的构造函数中显式调用了数组的默认构造函数，元素是否会被默认构造？ (在整数数组的情况下，这意味着进行零初始化)。

struct S
{
    S() : array() {}

    int array[SIZE];
};

...

S s;
// is s.array zero-initialized?

使用 gcc 的快速测试表明是这种情况，但我想确认我可以依赖这种行为。

(我注意到，如果我没有在结构构造函数中显式默认构造数组，则数组元素具有随机值。)

Answer 1

是(突出显示我的):

(C++03 8.5)

To value-initialize an object of type T means:

• if T is a class type (clause 9) with a user-declared constructor (12.1), then the default constructor for T is called (and the initialization is ill-formed if T has no accessible default constructor);

• if T is a non-union class type without a user-declared constructor, then every non-static > data member and baseclass component of T is value-initialized

• if T is an array type, then each element is value-initialized;

• otherwise, the object is zero-initialized

...

An object whose initializer is an empty set of parentheses, i.e., (), shall be value-initialized.