Answer 1

Because that's how C++ and most languages are designed. Most of the special characters are utilized for other purposes in the language. Beyond that, it's good for convention purposes as well, because using special characters in variable names is poor practice even if it was allowed. It's better to use descriptive names that fully encompass the purpose of the variable.

Answer 2

In fact it is possible but no one bother himself to make his code crappy and compiler-dependent. For example, $ (dollar sign) is a compiler extension that you might prefer to use it for naming identifiers. Regardless of your decision, chances are if somebody come up with your code with PHP background and s/he will be confused just because that freaky $. It's your right to slap together things and doing experiment, but don't allow your experiments escape into wild!

Answer 3

Reason : cuz C++ are not designed to carry out such command

Answer 4

What I think is special characters are used in every statements like " " , . ; so it may be too much complicated to understand and thus we are forbade from using special characters as variables......

( I am tooooo late)