Variables

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CONSTANTS

Constants are used in computer programs to store data that does not change. Constants are given self-documenting identifiers that should reflect the data being stored in them. An example of a constant could be Pi - 3.14

VARIABLES

in computer programming a variable may be required to store data that can change, Variables are given identifiers(names) that should reflect the data being stored in the variable

Static variables are stored in a location in memory and have a lifespan that lasts the entire time the program runs

Dynamic variable is assigned a new location in memory and has a lifespan that ends when the sub procedure in which it was defined ends.

A local variable is defined within a sub procedure and is only accessible from within the sub procedure. This is know as its scope

A global variable has a larger scope and is defined globally so is accessible from anywhere within a program.

What is the difference between a variable and a constant

my ans:

A constant is used in computer programs to store data that won't change (is fixed) and a variable is used in computer programs to store data that can change.

textbook ans:

A variable's value can be changed while the programs runs/ A constant's value is fixed it is a set value that cannot be changed while the program runs.

A variable should be radius = int(input())

A constant should be Pi 3.1415

A scope is a the range in which elements of a computer program can act, these elements include variables, constants, function or procedures.

B. Local Variable and Global Variable.