exactly mnemonic character string used to represent something else

allows to reuse definition from earlier points from the program

two types of type binding

done through explicit or implicit declaration

A name with fixed purpose

limitations are different for different languages

a statement in a program that lists variable names and specifies their types

means of associating variables with types through default conventions

maximum of 31 characters

an automatic detection of the type of an expression in a formal language

no limit but only the first 63 are significant; also, external names are limited to a maximum of 31 characters

usually are non-alphanumeric characters

has no declaration

All variable names must begin with dollar sign

a variable is bound to a type when it's assigned a value in an assignment statement

no limit, but implementers often impose one

specified through an assignment statement

All variable names begin with special characters, which specify the variable's type

the time period in which the variable or object has valid memory

an abstraction of a memory cell

lifetime is also called

getting a cell from some pool of variable cells

6 attributes of variables

putting a cell back into the pool

how we want to call our variable

memory address which it is associated

time during which it is bound to a particular memory cell

The contents of the location with which the variable is associated

categories of variables by lifetime

determines the range of values of variables and the set of operations that are defined for values of that type

bound to memory cells before execution begins and remains bound to the same memory cell throughout execution

means when we allocate storage for it and when we free its storage

storage bindings are created for variables when their declaration statements are elaborated, but whose types are statically bound

nameless memory cells that are allocated and deallocated by explicit directives "runtime instructions", specified by the programmer, which take effect during execution

accessibility of the variable

space and memory where we can store an item and can fetch it

these variables, which are allocated from and deallocated to the heap, can only be referenced through pointers or reference variables

if two variables' names can be used to access the same memory location

collection of storage cells whose organization is highly disorganized because of the unpredictability of its use

an object that stores a memory address

are created via pointers, reference variables, c and c++ unions

bound to heap storage only when they are signed value

variables which stores a memory address

allocation and deallocation caused by

are basically another name for an already existing variable

an association, such as between an attribute and an entity, or between an operation and a symbol

attachment of a name to an entity

The time at which a binding takes place

possible binding times

bind operator symbols to operations

bind floating point type to a representation

bind a variable to a type in C or Java

bind a C or C++ static variable to a memory cell

bind a non-static local variable to a memory cell

occurs before runtime and remains unchanged throughout program execution

occurs during execution or can change during execution of the program

occurs when the variable is assigned a value of a particular data type

a word that is special only in certain contexts

range of statements in which the variable is visible

local in a program unit or block if it is declared there

program unit or block are those that are visible within the program unit or block but are not declared there

allows a section of code to have its own local variables whose scope is minimized

always refers to its top level environment

binding names to non-local variables

search as the current lock and the successively all the calling functions