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statements;

}

The flow chart of the while statement is given below.

Flow chart of the while statement

Example

// this program computes the sum of 10 first integers starting from 1

#include<iostream.h>

int main()

{

const int N = 10

int sum = 0;

int count = 1; // initialize count

while (count<= N){

sum = sum + count;

count++; // increment count

}

cout<<“The sum is “<<sum<<endl;

return 0;

}

The output of the above program:

The sum is 55

In the above program, the loop incurs a counter-controlled repetition. Counter-controlled repetition requires:

  1. the name of a control variable (the variable count in this case);
  2. the initial value of the control variable ( count is initialized to 1 in this case)
  3. the condition that tests for the final value of the control variable (i.e., whether looping should continue) ;
  4. the increment (or decrement) by which the control variable is modified each time through the loop.

Example

#include<iostream.h>

int main()

{

int i;

i = 10;

while (i>= 1)

{

cout<<i<<" ";

i--; // subtract 1 from i

}

return 0;

}

The output of the above program:

  1. 9 8 7 6 5 4 3 2 1

Interactive while loops

Combining interactive data entry with the repetition capabilities of the while statement produces very adaptable and powerful programs.

Example

// Class average program with counter-controlled repetition

#include<iostream.h>

int main()

{

int total, // sum of grades

gradeCounter, // number of grades entered

grade, // one grade

average; // average of grades

// initialization phase

total = 0;

gradeCounter = 1; // prepare to loop

while ( gradeCounter<= 10 ) { // loop 10 times

cout<<"Enter grade: "; // prompt for input

cin>>grade; // input grade

total = total + grade; // add grade to total

gradeCounter = gradeCounter + 1; // increment counter

}

// termination phase

average = total / 10; // integer division

cout<<"Class average is "<<average<<endl;

return 0;

}

The following is a sample run of the above program:

Enter grade: 98

Enter grade: 76

Enter grade: 71

Enter grade: 87

Enter grade: 83

Enter grade: 90

Enter grade: 57

Enter grade: 79

Enter grade: 82

Enter grade: 94

Class average is 81

Sentinels

In programming, data values used to indicate either the start or end of a data series are called sentinels. The sentinel values must be selected so as not to conflict with legitimate data values.

Example

#include<iostream.h>

int main()

{

float grade, total;

grade = 0;

total = 0;

cout<<"\nTo stop entering grades, type in any number less than 0.\n\n";

cout<<"Enter a grade: ";

cin>>grade;

while (grade>= 0 )

{

total = total + grade;

cout<<"Enter a grade: ";

cin>>grade;

}

cout<<"\nThe total of the grades is "<<total<<endl;

return 0;

}

The following is a sample run of the above program:

To stop entering grades, type in any number less than 0.

Enter a grade: 95

Enter a grade: 100

Enter a grade: 82

Enter a grade: -2

The total of the grades is 277

Break statement

The break statement causes an exit from the innermost enclosing loop statement.

Example:

while( count<= 10)

{

cout<<“Enter a number: “:

cin>>num;

if (num>76){

cout<<“you lose!\n”;

break;

}

else

cout<<“Keep on trucking!\n”;

count++;

}

//break jumps to here

Questions & Answers

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 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
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
How can I make nanorobot?
Lily
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
NANO
how can I make nanorobot?
Lily
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
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.
Tarell
what is the actual application of fullerenes nowadays?
Damian
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.
Tarell
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Mueller 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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