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A postfix operator is placed after a variable and returns the value of the operand before the operation is performed.

Prefix and postfix operators have different effects when used in a statement

b = ++a;

will first increase the value of a to 6, and then assign that new value to b. It is equivalent to

a = a +1;

b = a;

On the other hand, execution of the statement

b = a++;

will first assign the value of 5 to b, and then increase the value of a to 6. It is now equivalent to

b = a;

a = a + 1;

The decrement operators are used in a similar way.

Example

// Preincrementing and postincrementing

#include<iostream.h>

int main()

{

int c;

c = 5;

cout<<c<<endl; // print 5

cout<<c++<<endl; // print 5 then postincrement

cout<<c<<endl<<endl; // print 6

c = 5;

cout<<c<<endl; // print 5

cout<<++c<<endl; // preincrement then print 6

cout<<c<<endl; // print 6

return 0; // successful termination

}

The output of the above program:

5

5

6

5

6

6

Formatting number for program output

Besides displaying correct results, a program should present its results attractively with good formats.

Stream manipulators

Stream manipulator functions are special stream functions that change certain characteristics of the input and output.

The main advantage of using manipulator functions is they facilitate the formatting of the input and output streams.

- setw(): The setw() stands for set width. This manipulator is used to specify the minimum number of the character positions on the output field a variable will consume.

- setprecision(): The setprecision() is used to control the number of digits of an output stream display of a floating point value. Setprecision(2) means 2 digits of precision to the right of the decimal point.

To carry out the operations of these manipulators in a user program, you must include the header file<iomanip.h>.

Example

#include<iostream.h>

#include<iomanip.h>

int main()

{

cout<<setw(3)<<6<<endl

<<setw(3)<<18<<endl

<<setw(3)<<124<<endl

<<"---\n"

<<(6+18+124)<<endl;

return 0;

}

The output of the above program:

Output of above program

Example:

cout<<“|”<<setw(10)

<<setioflags(ios::fixed)<<setprecision(3)<<25.67<<”|”;

causes the printout

Output of above code segment

- setiosflags: This manipulator is used to control different input and output settings.

setioflag(ios::fixed) means the output field will use conventional fixed-point decimal notation.

setiosflag(ios::showpoint) means the output field will show the decimal point for floating point number.

setiosflag(ios::scientific) means the output field will use exponential notation.

Note: In the absence of the ios::fixed flag, a floating point number is displayed with a default of 6 significant digits. If the integral part of the number requires more than 6 digits, the display will be in exponential notation.

Below are some other format flags for use with setiosflags().

Flags for use with setiosflags()

Example

// This program will illustrate output conversions

#include<iostream.h>

#include<iomanip.h>

int main()

{

cout<<"The decimal (base 10) value of 15 is "<<15<<endl

<<"The octal (base 8) value of 15 is "

Questions & Answers

what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
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
Rafiq
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
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
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
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.
Bharti
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
Daniel
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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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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