Any instance/value is *Valid* if all of its [[Invariant|Invariants]] hold true. >[!example] An invariant of a C-style string is that it is [[Null Terminated]], therefore when this value ($\text{char}*$) is valid would look like this. > >```cpp >const char* string; >// 'string' is is currently 'junk data', >// therefore 'string' is invalid. > >string = "This string is now null terminated and valid."; >```