<< Chapter < Page Chapter >> Page >
This chapter gets you started immediately writing some simple C++ programs and helps you to understand some basic elements in any high level programming language such as data types, arithmetic operators, output statements and assignment statements.

Program structures

Modular programs

A large program should be organized as several interrelated segments, arranged in a logical order: The segments are called modules. A program which consists of such modules is called a modular program.

In C++, modules can be classes or functions.

We can think of a function as a program segment that transforms the data it receives into a finished result.

Each function must have a name. Names or identifiers in C++ can made up of any combination of letters, digits, or underscores selected according to the following rules:

  • Identifiers must begin within an uppercase or lowercase ASCII letter or an underscore (_).
  • You can use digits in an identifier, but not as the first character. You are not allowed to use special characters such as $,&, * or %.
  • Reserved words cannot be used for variable names.

Examples:

DegToRadintersectaddNums

FindMax1_densityslope

Examples of invalid identifiers:

1AB3

E%6

while

Note: C++ is a case-sensitive language (i.e. upper and lower case characters are treated as different letters).

The main() function

The main() function is a special function that runs automatically when a program first executes.

All C++ programs must include one main() function. All other functions in a C++ program are executed from the main() function.

The first line of the function, in this case int main() is called a function header line.

The function header line contains three pieces of information:

  1. What type of data, if any, is returned from the function.
  2. The name of the function
  3. What type of data, if any, is sent into the function.

int main()

{

program statements in here

return 0;

}

Note: The line

return 0;

is included at the end of every main function. C++ keyword return is one of several means we will use to exit a function. When the return statement is used at the end of main as shown here, the value 0 indicates that the program has terminates successfully.

The cout object

The cout object is an output object that sends data given to it to the standard output display device.

To send a message to the cout object, you use the following pattern:

cout<<“text”;

The insertion operator,<<, is used for sending text to an output device.

The text portion of the statement is called a text string. Text string is text that is contained within double quotation marks.

Consider the following program.

Example

#include<iostream.h>

int main()

{

cout<<"Hello world!”;

return 0;

}

The output of the above program:

Hello world!

Preprocessor directives

Before you can use any runtime libraries in your program, you must first add a header-file into your program, using the #include statement. A header file is a file with an extension of .h that is included as part of a program and notifies the compiler that a program uses run-time libraries.

One set of classes you will use extensively in the next few chapters is the iostream classes. The iostream classes are used for giving C++ programs input capabilities and output capabilities.

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
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
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
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
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
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
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Good
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?

Ask