How do define anonymous functions in C++?

C++11 added lambda functions to the language. The previous versions of the language (C++98 and C++03), as well as all current versions of the C language (C89, C99, and C11) do not support this feature. The syntax looks like:

[capture](parameters)->return-type{body}

For example, to compute the sum of all of the elements in a vector:

std::vector<int> some_list;
int total = 0;
for (int i=0;i<5;i++) some_list.push_back(i);
std::for_each(begin(some_list), end(some_list), [&total](int x) {
  total += x;
});