The difference between new node() and new node?

[remlostime]

now, I define the struct following:
struct node
{
bool match;
node* child[27];
};

What's the difference between
1) node *Trie=new node(); and 2) node *Trie = new node;

 

[Linlin Yan]

now, I define the struct following:
struct node
{
        bool match;
        node* child[27];

};

What's the difference between
1) node *Trie=new node(); and 2) node *Trie = new node;

no difference.

 

[James Kanze]

now, I define the struct following:
struct node
{
bool match;
node* child[27];
};

What's the difference between
1) node *Trie=new node(); and 2) node *Trie = new node;

new Node() zero initializes the data, i.e. match will be false,
and all of the pointers will be NULL. new Node doesn't; the
contents are undefined, and reading them (before having set them
otherwise) is undefined behavior.

 

[Juha Nieminen]

new Node() zero initializes the data, i.e. match will be false,
and all of the pointers will be NULL. new Node doesn't

Btw, is there anything equivalent for allocating arrays?

 

[Thomas J. Gritzan]

Btw, is there anything equivalent for allocating arrays?

Sure.

// allocates uninitialized ints
int* arry1 = new int[100];

// allocates ints initialized to 0 on recent (=conformant) compilers
int* arry2 = new int[100]();

// allocates ints initialized to 0 on all compilers
std::vector<int> arry3(100);