foo() 和 foo 未必相同

此文有问题

struct foo
{
    int val;
};

#include

int main( void )
{
    using namespace std;

    foo* p1 = new foo();
    foo* p2 = new foo;

    foo* p3 = new foo[2]();
    foo* p4 = new foo[2];

    cout << p1->val << endl; // val被初始化为int()，即0
    cout << p2->val << endl; // val为随机值

//    cout << p3->val << endl; // val被初始化为int()，即0
//    cout << p4->val << endl; // val为随机值
   
    return 0;
}

2008-01-10:
ISO/IEC 14882:2003(E) 中 5.3.4 之 15
— If the new-initializer is omitted:
    — If T is a (possibly cv-qualified) non-POD class type (or array thereof), the object is default-initialized(8.5). If T is a const-qualified type, the underlying class type shall have a user-declared default constructor.
    — Otherwise, the object created has indeterminate value. If T is a const-qualified type, or a (possibly cv-qualified) POD class type (or array thereof) containing (directly or indirectly) a member of const-qualified type, the program is ill-formed;
— If the new-initializer is of the form (), the item is value-initialized (8.5);