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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

find the 15th term of the geometric sequince whose first is 18 and last term of 387
Jerwin Reply
The given of f(x=x-2. then what is the value of this f(3) 5f(x+1)
virgelyn Reply
hmm well what is the answer
Abhi
how do they get the third part x = (32)5/4
kinnecy Reply
can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
ninjadapaul
20/(×-6^2)
Salomon
okay, so you have 6 raised to the power of 2. what is that part of your answer
ninjadapaul
I don't understand what the A with approx sign and the boxed x mean
ninjadapaul
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
Salomon
I'm not sure why it wrote it the other way
Salomon
I got X =-6
Salomon
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
ninjadapaul
oops. ignore that.
ninjadapaul
so you not have an equal sign anywhere in the original equation?
ninjadapaul
hmm
Abhi
is it a question of log
Abhi
🤔.
Abhi
Commplementary angles
Idrissa Reply
hello
Sherica
im all ears I need to learn
Sherica
right! what he said ⤴⤴⤴
Tamia
hii
Uday
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
Kevin Reply
a perfect square v²+2v+_
Dearan Reply
kkk nice
Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
Kim
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Al
y=10×
Embra Reply
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
Nancy Reply
rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
how do you translate this in Algebraic Expressions
linda Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele Reply
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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