A condition that is assumed to be true at the beginning of a function. If the precondition is not true, the function may not work. It is often a good idea for functions to check their preconditions, if possible.
In general use, a class is a user-defined type with member functions. In C++, a class is a structure with private instance variables.
accessor function
A function that provides access (read or write) to a private instance variable.
invariant
A condition, usually pertaining to an object, that should be true at all times in client code, and that should be maintained by all member functions.
precondition
A condition that is assumed to be true at the beginning of a function. If the precondition is not true, the function may not work. It is often a good idea for functions to check their preconditions, if possible.
postcondition
A condition that is true at the end of a function.
