Is there an equvalent to Dim/var in C++?

I'm new to C++ and i have a case where vb.nets Dim or C#s var would help me greatly.

i googled around and i found no questions for th开发者_Python百科is? (although search terms with var or dim and C++ seemed to stray easy)

is there an equivalent for this?

Not in the current standard.

However, the new version that is probably due this year (most likely called C++11, but it's also still often referred to as C++0x) has auto that does that same thing as var. It's already supported by recent versions of all big compilers.

For example:

auto MyValue = SomeFunction(); // The compiler will figure out the type of MyValue

You're probably looking for the auto keyword in C++0x.

As per my comment, Dim does a lot of different things.

If you are looking for a variable that can be anything, or something that will work like

Dim var
var = 1
var = "Hello"
Set var = new Thing

You can use

1. void* and cast
2. a union type of all the possible thing this variable can be, if these are known in advance
3. boost::variant<> - discriminated union, also if all types are known in advance
4. boost::any - any type you want, the closest I can think of to Dim

Cliff notes:

boost::any will work for you

In C++ you can use unions or use a base class and inheritance.

The union allows you to have an area in memory and organize it in different ways. A base class and inheritance allows you to treat child objects in a common manner.

union
{
  int value;
  double floating_point;
};

In the union above, the integer value and the double precision floating_point variables occupy the same area (within the union).

The union may be the closest data structure to a variant record. The Boost library also has a variant data structure, search the web for "boost variant".