What does `new auto` do?

Question

What does it mean when I use `new auto`? Consider the expression: ``` new auto(5) ``` What is the type of the dynamically allocated object? What is the type of the pointer it returns?

Accepted Answer

In this context, `auto(5)` resolves to `int(5)`.

You are allocating a new `int` from the heap, initialized to `5`.

(So, it's returning an `int *`)

Quoting Andy Prowl's resourceful answer, with permission:

Per Paragraph 5.3.4/2 of the C++11 Standard:

If the `auto` type-specifier appears in the type-specifier-seq of a new-type-id or type-id of a new-expression, the new-expression shall contain a new-initializer of the form

```
( assignment-expression )
```

The allocated type is deduced from the new-initializer as follows: Let `e` be the assignment-expression in the new-initializer and T be the new-type-id or type-id of the new-expression, then the allocated type is the type deduced for the variable `x` in the invented declaration (7.1.6.4):

```
T x(e);
```

[ Example:

```
new auto(1); // allocated type is int
auto x = new auto(’a’); // allocated type is char, x is of type char*
```

—end example ]

What does `new auto` do?

Solution

Problem