使用new时的数组初始化

Question

In C# I could do this:

char[] a = new char[] {'a', 'a', 'a'};

But can I do something like that in C++? I tried:

char *a = new char [] {'a', 'a', 'a'};

But it doesn't compile.

Answer 1

why not just do this? :

char a[] = {'a', 'a', 'a'};

Also avoid using arrays completely. Use std::vector

Answer 2

This is a bug in the C++ spec (which doesn't let this simple construct to compile). You need to supply the size

char *a = new char [3] {'a', 'a', 'a'};

See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1469 . Note that if you parenthesize the type name it is a type-id and not a new-type-id and hence syntactically allows you to omit the size expression. So you may be able to find an implementation that allows you to say

char *a = new (char[]){'a', 'a', 'a'};

Althought it is clear that it wasn't the explicit intent that this is possible (and some rules in the new paragraphs can be interpreted to forbid it).

Answer 3

You probably don't want to use an array in C++. Use a std::vector instead.

You can even initialise it to 3 'a's.

std::vector<char> vectorOfChars(3, 'a');

If your compiler supports C++11, you can even use an initialiser list.

std::vector<char> vectorOfChars{'a', 'a', 'a'};

Answer 4

我想你想要的是这个：

   const char a[] = {'a', 'a', 'a'};

Answer 5

Yes, you can do it like;

char a[] = {'a', 'a', 'a'};

Check out Arrays (C++) from MSDN .

Answer 6

string a = "aaa"; a[0] , a[1] ..etc This will be much easier if you wanna make 2-D arrays of string..etc