c++ - Default constructor with empty brackets -

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is there reason empty set of round brackets (parentheses) isn't valid calling default constructor in c++?

myobject  object;  // ok - default ctor myobject  object(blah); // ok  myobject  object();  // error

i seem type "()" automatically everytime. there reason isn't allowed?

most vexing parse

this related known "c++'s vexing parse". basically, can interpreted compiler declaration interpreted declaration.

another instance of same problem:

std::ifstream ifs("file.txt"); std::vector<t> v(std::istream_iterator<t>(ifs), std::istream_iterator<t>());

v interpreted declaration of function 2 parameters.

the workaround add pair of parentheses:

std::vector<t> v((std::istream_iterator<t>(ifs)), std::istream_iterator<t>());

or, if have c++11 , list-initialization (also known uniform initialization) available:

std::vector<t> v{std::istream_iterator<t>{ifs}, std::istream_iterator<t>{}};

with this, there no way interpreted function declaration.


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