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In the above example, the Payroll class has two parameterized constructor functions: one for states that have a state income tax and one for states that do not have a state income tax.

Initialization lists

Initialization lists , or member initialization lists, are another way of assigning initial values to a class’s data members.

An initialization list is placed after a function header’s closing parenthesis, but before the function’s opening curly braces.

Example: Given the simple constructor that assigns parameter values to the Payroll class.

Payroll::Payroll(double dFed, double dState){

dFedTax = dFed;

dStateTax = dState;


You can use initialization list to rewrite the above constructor function.

Payroll::Payroll(double dFed, double dState)

:dFedTax(dFed), dStateTax(dState){


Parameterized constructors that uses default arguments

To create a parameterized constructor that uses default arguments, we can put the default values at the constructor prototype.

In the following example, the class Employee has a constructor with the prototype:

Employee(const int id = 999, const double hourly = 5.65);

This format provides the constructor function with default values for two arguments. When we create an Employee object, the default values in the constructor function prototype are assigned to the class variables.



class Employee{


int idNum;

double hourlyRate;


Employee(const int id = 9999, const double hourly = 5.65);

void setValues(const int id, const double hourly);

void displayValues();


Employee::Employee(const int id, const double hourly)


idNum = id;

hourlyRate = hourly;


void Employee::displayValues()


cout<<”Employee #<<idNum<<” rate $”<<

hourlyRate<<“ per hour “<<endl;


void Employee::setValues(const int id, const double hourly)


idNum = id;

hourlyRate = hourly;


int main(){

Employee assistant;

cout<<“Before setting values with setValues()”<<endl;


assistant.setValues(4321, 12.75);

cout<<“After setting values with setValues()”<<endl;


return 0;


The output of the above program:

Before setting values with setValues()

Employee #9999 rate $5.65 per hour

After setting values with setValues()

Employee #4321 rate $12.75 per hour


A default destructor cleans up any resources allocated to an object once the object is destroyed. The default constructor is sufficient for most classes, except when you have allocated memory on the heap.

To delete any heap variables declared by your class, you must write your own destructor function.

You create a destructor function using the name of the class, the same as a constructor function, preceded by a tilde ~. Destructor functions cannot be overloaded. A destructor accepts no parameter and returns no value.

A destructor is called in two ways:

- when a stack object loses scope when the function in which it is declared ends.

- when a heap object is destroyed with the delete operator.

The destructor itself does not actually destroy the object – it performs termination house keeping before the system reclaims the object’s memory so that memory may be reused to hold new objects.

Questions & Answers

what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
How can I make nanorobot?
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
how can I make nanorobot?
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
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Source:  OpenStax, Programming fundamentals in c++. OpenStax CNX. Jul 29, 2009 Download for free at http://cnx.org/content/col10788/1.1
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