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Glossary of Terms

abstraction:
define essential properties and behaviors while hiding the inessential details.
 
alternate constructor:
A constructor with parameters that is called when a newly created object has arguments. There may be several alternate constructors which are resolved by function overloading rules.
 
argument:
actual data object which is passed to a function during a function call. The value or reference to this argument will be bound to the function parameter as appropriate.
 
attribute:
a property of an object. data whose value defines a characteristic of the object.
 
base class:
a class from which another class inherits data and functions forming an IS-A relationship between the classes
 
binary function:
A function which has two arguments, many binary functions use special operator symbols and infix notation
 
call by reference:
a method of passing arguments into a function which references that argument allowing it to be modified (unless there is a const modifier). Sometimes used with const modifier for reasons of efficiency (reference is basically a pointer and so usually takes only 32 bits).
 
call by value:
a method of passing arguments into a function in which a copy is made of the argument's value (state) and placed in the parameter (which acts like a local variable of the function). Changes to value parameters have no effect on the value of the argument.
 
class:
A set of objects defined by common attributes or properties (data members) and common behavior or operations (function members). see terminology
 
component:
group of objects that work together
 
 
composition relationship:
See HasA relationship
 
constructor:
A class member function that is called whenever a new call object is created. Default constructors have no parameters. Alternate (or non-default) constructors can have parameters. There can be several constructors for a given class.
 
constructor-initializer:
special syntax for invoking alternate constructors for data members of a class. Needed since all data members are constructed BEFORE the containing class is constructed. Allows arguments to be passed from the containing classes alternate constructor to the data member alternate constructors. SYNTAX: ContainingClassConstructor(parameterList) : dataMember(constructorArguments)
 
data member:
data variables in a class. also known as property or attribute.
 
deep copy:
when an object contains pointers, a deep copy will follow the pointers and make a copy of all objects pointed at. For example. A deep copy of a linked list, will copy every node in the list so that two identical but distinct lists exist.
 
default constructor:
A constructor for a class which has no parameters and is called whenever a new object is created without arguments.
 
derived class:
A class which inherits data members and functions from a base class forming an IS-A relationship with that class.
 
encapsulation:
ability to hide information about the details of an abstraction and to protect those details from unwarranted use. This means that the details could be changed without changing the abstraction. The class and function are the primary encapsulation mechanisms in C++.
 
function prototype:
Information for the compiler and user about how to use a function. Gives function name, return type, a parameter list (number and type of arguments in order)
 
has-a relationship:
A relationship between classes in which one class has data member which are from the other class. also known as a composition relationship
 
header file:
files containing class definitions, function prototypes, global data and other information of general interest to a program.
 
hierarchy:
a relationship between modules where one module is the parent or controller of another module. Inheritance (IS-A) relationships between classes and calling/called relationships between functions are examples of hierarchies.
 
infix functions:
a binary functions where the function name appears in between the arguments of the function
Usually infix functions use special functions names called operators (e.g. +, -, *, /, << , >>)
 
inheritance:
Allows the definition of new classes from old classes where the new class can reuse existing data and function members, modify them or add new members. (see also IS-A relationship)
 
instance:
A particular object in a class, usually associated with a variable name. An instance has state which can be changed by the modifiers of the class.
 
implementation file:
file containing member function defintions (i.e. function bodies) usually associated with a header file.
 
is-a relationship:
An inheritance relationship between classes whereby one class (derived class) is a specialization of another class (called the base class)
 
local variable:
a variable whose visibility and lifetime are limited to the function in which it is defined. Thus a local variable cannot be accessed outside the function and only is allocated when the function is invoked (Called). (unless it has the "static" modifier).
 
member access operator:
the single dot ('.') which is used to access both the data and function members of an object. general syntax: objectID.MemberName
 
member function:
functions defined for a class. also known as the bahaviors of the class, the methods of the class or the operations of the class.
 
modularity:
division of a program into units (modules) which have a well defined interface. modules are building blocks for a program.
 
non-default constructor:
see alternate constructor
 
objects:
any thing, real or abstract about which we store data and those methods (operations) that manipulate that data (Martin/Odell) see terminology
 
object-oriented analysis:
process of examining the application requirements to discover the classes and object, their state, behaviors and relationships in the vocabulary of the problem domain.
 
object-oriented design:
is a design method that breaks the problem into class and object abstractions to logically structure the solution
 
 
operator:
Special functions names which are represented by special symbols (e.g. +, -, *, /, << , >>, ++)
 
overloading functions:
results whenever the same function name is used for more than one function. The compiler resolves which function should be called by examining the function's signature: that is, the number and type of the parameters. When types differ but are convertible (e.g. int to float), then a best match is made (see pages 75-77 for details)
 
parameter:
place holder in a function definition into which the value or reference to the actual function argument (during a function call) will be bound (copied). This is a variable name that is local to the function body.
 
polymorphism:
Using the same name to denote objects of different (but related by inheritance) types
 
post-condition:
what must be try after a function executes. Usually applies to the output data or data members of a class. With the pre-condition forms a contract between the writer of a function and the user of that function.
 
pre-condition:
says what must be try before a function is executed. Usually places restrictions on the values on the input parameters.
 
prototype:
see function prototype
 
pseudocode:(a1)
is structured English version of the program which uses English nouns and verbs and C++ control structure syntax to express the way the program should work (the algorithm)
 
 
reference:
see call by reference
 
scope resolution operator:
the double colon ("::") which is used to associate a member function with its class. Needed to disambiguate function definitions for the compiler.
 
shallow copy:
when an object contains pointers, a shallow copy only makes a copy of the pointers and not the objects pointed at. For example. A shallow copy of a linked list, will copy only the head pointer, both the original and copied head pointers will point to the same list.
 
signature of a function:
function name and the order and type of its parameters. (NOTE: this information is contained in the function prototype).
 
state (of object):
the values of an objects attributes, the properties of an object, the values of the object's data members
 
strongly typed language:
Language which requires that only compatible types are used in expressions. Helps catch incorrect usage of variables.
 
value:
see call by value

 


Copyright chris wild 1998.
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Last updated: October 14, 1998.