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In the last chapter, we explored how results are displayed and how numerical data are stored and processed using variables and assignment statements. In this chapter, we complete our introduction to the basics of C++ by presenting additional processing and input capabilities.

Assignment operators

Assignment operator (=) is used for assignment a value to a variable and for performing computations.

Assignment statement has the syntax:

variable = expression;

Expression is any combination of constants, variables, and function calls that can be evaluated to yield a result.

Example:

length = 25;

cMyCar = “Mercedes”;

sum = 3 + 7;

newtotal = 18.3*amount;

slope = (y2 – y1)/(x2 – x1);

The order of events when the computer executes an assignment statement is

- Evaluate the expression on the right hand side of the assignment operator.

- Store the resultant value of the expression in the variable on the left hand side of the assignment operator.

Note:

1. It’s important to note that the equal sign in C++ does not have the same meaning as an equal sign in mathematics.

2. Each time a new value is stored in a variable, the old one is overwritten.

Example

// This program calculates the volume of a cylinder,

// given its radius and height

#include<iostream.h>

int main()

{

float radius, height, volume;

radius = 2.5;

height = 16.0;

volume = 3.1416 * radius * radius * height;

cout<<"The volume of the cylinder is "<<volume<<endl;

return 0;

}

The output of the above program:

The volume of the cylinder is 314.16

We can write multiple assignments , such as a = b = c = 25;. Because the assignment operator has a right-to-left associativity, the final evaluation proceeds in the sequence

c = 25;

b = 25;

c = 25;

Data type conversion across assignment operator

Note that data type conversion can take place across assignment operators, that is, the value of the expression on the right side of the assignment operator is converted to the data type of the variable to the left side of the assignment operator.

For example, if temp is an integer variable, the assignment temp = 25.89 causes the integer value 25 to be stored in the integer variable temp.

Assignment variations

C++ also use a shorthand notation to perform an operation and an assignment at the same time. This is denoted by an operator followed by an equal sign. For example, to add 4 to the variable x and assign x to the result, you say: x += 4. Figure 1 illustrates assignment operator and all assignment variations.

Variations of assignment

Assignment statements such as sum += 10 or its equivalent, sum = sum + 10, are very common in C++ programming.

Increment and decrement operators

For the special case in which a variable is either increased or decreased by 1, C++ provides two unary operators: increment operator and decrement operator .

Increment operator and decrement operator

The increment (++) and decrement (--) unary operators can be used as prefix or postfix operators to increase or decrease value.

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

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
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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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