15.08.txt

Exercise 15.8: Define static type and dynamic type.

By Faisal Saadatmand

A static type is the type of a variable or an expression that is known at
compile time. "It is the type with which a variable is declared or that an
expression yields. The dynamic type is the type of the object in memory that
the variable or expression represents." (p. 601) It is not known until runtime.
Put differently, a static type is the type that a variable or an expression
'ought' to have, which is locked during compilation, and the dynamic type is
the 'actual' type the variable holds or the expression yields at runtime. An
expression that is neither a reference nor a pointer will always have identical
static and dynamic types. A reference or a pointer, on the other hand, could
have a different static type from its dynamic type at runtime.