Is there any kind of “expression class” (C++)

Question

I am creating a game that lets the player enter input, changes some states, then checks if a \"goal value\" is true (obviously this description is muchly simplified), and I

Answer 1

I'm thinking you can define your own class and work around using the 'assert' keyword, but I may have understood the question wrong.

http://www.cplusplus.com/reference/clibrary/cassert/assert/