为什么我不能用c ++中的new调用参数化构造函数？

Question

If you know the issue,

Assume I have a class A whose CTOR receives an integer;

I cannot do the following :

A* arr = new A[3](A(2), A(3), A(5));

Or any other way to initialize several members of an array. I read around, its just not possible.

My question is why, why can I do

A arr[3] = {A(1), A(2), A(3)};

but I can not do the above? Memory-wise or whatever.

Thank you very much!

Answer 1

The reason you can't do this in current standard C++ (referred to as C++03) is historical. This will be cleaned up in the upcoming C++ standard (currently expected to be released this year, which would make it C++11), which will introduce what's called "uniform initialization syntax".

According to Stroustrup's C++0x FAQ , you can then write

A* p = new A[3] {A(1), A(2), A(3)};

There's a pretty good chance your compiler is actually already supporting this.

Answer 2

I believe you are trying to do "uniform initialization" which is included in C++0x. I don't get why the initialization list uses A(int) parts, I'd just do this (which is accepted by C++98/03:

A arr[3] = {1, 2, 3};