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Do the parentheses after the type name make a difference with new?
I believe this question was already asked, but I cannot find it with a quick search.
Foo ob* = new Foo; Foo ob* = new Foo(); Is there a difference between these two ways of creating an object in C++? If not then is one of these considered a bad practice? Does every compiler treats it the same?
The first is default initialization, the second is value initialization. If Foo is of class type, they both invoke the default constructor. If Foo is fundamental (e.g. typedef int Foo;), default initialization performs no initialization, while value-initialization performs zero-initialization.
For class types and arrays, the initialization proceeds recursively to the members/elements in the expected way.
There is no difference, other than the fact that if Foo is a built-in type then the former does not value-initialise it.
So:
new int; // unspecified value new int(); // 0 This matches up nicely with "normal" allocation for built-ins, too:
int x; // unspecified value int x = 0; // well, you can't do `int x()`, but, if you could... 
int x{}; nowadays :-)int x((int()); or so.