Chapter 6, Problem 20PS

Program Plan Intro

Static type checking:

• A language is statically-typed if the type of a variable is known at compile time.
• It allows many type errors to be caught early in the development cycle.
• Static typing usually results in compiled code which executes more quickly because when the compiler knows the exact data types which are in use, it can produce optimized machine code.
• It evaluate only the type information which can be determined at compile time, but are able to verify that the checked conditions hold for all possible executions of the program, which eliminated the need to repeat type checks every time the program is executed.

Dynamic type checking:

• It is the process of verifying the type safety of a program at runtime.
• Most type-safe languages include some form of dynamic type checking, even if they also have a static type checker.
• The reason for this is that many useful features or properties are difficult or impossible to verify statically.