What is the difference between “compile time” and “run time”?

Question

I do not understand what is meant by the terms \"compile time\" and \"run time\" (or \"runtime\").

I\'m also a bit confused about what \"value type\" and \"reference ty

Answer 1

Value type variable means variable who can store its own value directly.
Reference type variable means variable who store reference (i.e.address of value) of their value instead of storing value directly.