<< Chapter < Page Chapter >> Page >


long int days;

unsigned int num_of_days;

The reserved words unsigned int are used to specify an integer that can only store nonnegative numbers.

The signed and unsigned quantifiers tell the compiler how to use the sign bit with integral types and characters (floating-point numbers always contain a sign). An unsigned number does not keep track of the sign and thus has an extra bit available, so it can store positive numbers twice as large as the positive numbers that can be stored in a signed number.

Integer types with quantifiers

When you are modifying an int with short or long, the keyword int is optional.

Now all the built-in data types provide by C++ are given in the following list, ordered descendingly by the size of the data types.

Data types


long double



unsigned long

long int

unsigned int


short in


Data type conversions

An expression containing both integer and floating point operands is called a mixed mode expression.


int a;

float x = 2.5;

a = x + 6; // x + 6 is a mixed mode expression

Note: We should avoid mixed-mode expression.


char Ch;

int In1 = 129, In2, In3;

double Real1 = 12.34, Real2;

What happens with the following mixed mode assignments?

Ch = In1/2 + 1; // Right side = 65; assigns ‘A’ to Ch

In2 = Ch + 1; // Right side = 66; assigns 66 to In2

Real2 = In1/2; // Right side = 64; assigns 64.0 to Real2

In3 = Real1/2.0 // Right side = 6.17; truncates this value and assigns 6 to In3

The general rules for converting integer and floating point operands in mixed mode arithmetic expressions were presented as follows:

  1. If both operands are either character or integer operands:
    • when both operands are character, short or integer data types, the result of the expression is an integer value.
    • when one of the operand is a long integer, the result is a long integer, unless one of the operand is an unsigned integer. In the later case, the other operand is converted to an unsigned integer value and the resulting value of the expression is an unsigned value.
  2. If any one operand is a floating point value:
    • when one or both operands are floats, the result of the operation is a float value;
    • when one or both operands are doubles, the result of the operation is a double value;
    • when one or both operands are long doubles, the result of the operation is a long double value;

Notice that converting values to lower types can result in incorrect values. For example, the floating point value 4.5 gives the value 4 when it is converted to an integer value. The following table lists the built-in data types in order from “highest type” to “lowest type”.

Determining storage size

C++ provides an operator for determining the amount of storage your compiler allocates for each data type. This operator, called the sizeof() operator.





The item in parentheses can be a variable or a data type.


// Demonstrating the sizeof operator


int main()


char c;

short s;

int i;

long l;

float f;

double d;

long double ld;

cout<<"sizeof c = "<<sizeof(c)

Questions & Answers

How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
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.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get the best Algebra and trigonometry course in your pocket!

Source:  OpenStax, Programming fundamentals in c++. OpenStax CNX. Jul 29, 2009 Download for free at http://cnx.org/content/col10788/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Programming fundamentals in c++' conversation and receive update notifications?