8/8/2019 Program to Find a Prime Number

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write a program to find out whether agiven number is prime...

<< Back to: comp.lang.c Answers to Frequently Asked Questions (FAQ List)

Question by urvi

Submitted on 1/1/2004

Related FAQ: comp.lang.c Answers to Frequently Asked Questions (FAQ List)

Rating: Rate this question:

write a program to find out whether a given number is prime or not.

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8/8/2019 Program to Find a Prime Number

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Answer by golla.satyanarayana

Submitted on 3/17/2004Rating: Rate this answer:

main(){int a,c=0,i,n;printf("enter the number to be checked");scanf("%d",&n);for(i=1;i<=n;i++)

{a=n%i;

if(a=0){

c=c+1;}

}if (c=2)

{ printf("the given number is prime"); }else

printf("the given number is not prime");}

Answer by Abhilash

Submitted on 1/28/2005

Rating: Rate this answer:

#include<stdio.h>#include<conio.h>void main()

{int no,i;clrscr();printf(" Enter the Number U want to check:");scanf("%d",&no);i=2;while(i<=no-1){

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if(no%i==0){

printf(" %d is not Prime number",no );break;

}

i=i+1;}if(no==i)

printf("%d is a prime Number",no);getch();}

Answer by james

Submitted on 2/9/2005

Rating: Not yet rated Rate this answer:

main(){int n,i,a;printf("enter the number");scanf("%d",&n);if(n==1)printf("it is neither prime nor composite");

for(i=2;i<=n;i++){a=n%i;if(a==0){printf("the number is not a prime number");}else{printf("the number is prime");}

}}

Answer by naveen

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8/8/2019 Program to Find a Prime Number

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Submitted on 5/19/2005

Rating: Not yet rated Rate this answer:

void main()

{int i,n;printf("enter the number to be checked");scanf("%d",&n);for(i=2;i<=n;i++)

{if(n%i==0)printf("The number is prime number")

}else

printf("the given number is not a prime number");getch();}

Answer by goli

Submitted on 2/16/2006

Rating: Not yet rated Rate this answer:

main(){int n, i;printf ("Enter any number \n");scanf("%d", &n);for (i=2 ; i <=n/2 ; i++)

{if(n % i ==0){

printf(" Its not a prime number\n");break;

}

}printf("Its a prime number\n ");

}

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8/8/2019 Program to Find a Prime Number

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Answer by romeo

Submitted on 2/20/2006

Rating: Not yet rated Rate this answer:

#include<stdio.h>#include<conio.h>#define TRUE 1#define FALSE 0

int prime(int number){

int i=2,flg=TRUE,c;while(i<number){

c = number %i;

if(c==0)flg=FALSE;

i++;}return flg;

}

void main(){

int num,c;int is_prime;

clrscr();printf("Enter a number: ");scanf("%d",&num);

is_prime = prime(num);

if(is_prime==1)puts("Prime Number");

elseputs("Not a Prime Number");

getch();

}

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Answer by supriya

Submitted on 3/29/2006

Rating: Not yet rated Rate this answer:

main(){int a,c=0,i,n;printf("enter the number to be checked");scanf("%d",&n);for(i=1;i<=sqrt(n);i++)

{a=n%i;if(a=0)

{c=c+1;

}}

if (c=2){ printf("the given number is prime"); }

elseprintf("the given number is not prime");

}

Answer by raihana66

Submitted on 5/16/2006

Rating: Not yet rated Rate this answer:

int n,n1;print("enter number");scanf("%i",&n);if(n%2=0&&n1=2)printf("prime number");elseprintf("not primenumber);

Answer by raihana66

Submitted on 5/16/2006

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int n,n1;printf("enter number");scanf("%i",&n);if(n%2=1&&n1=2)printf("prime number");elseprintf("not prime number);

Answer by raihana66

Submitted on 5/16/2006

Rating: Not yet rated Rate this answer:

int n,c);printf("enter number");scanf("%i",&n);if(n%2=0&&n>=1&&c=2)printf("prime number");elseprintf("not prime number);

Answer by raihana

Submitted on 5/16/2006

Rating: Not yet rated Rate this answer:

main(){int a,c,i,n;printf("enter the number to be checked");scanf("%d",&n);if(i=1&&i<=n&&i++)

a=n%i;if(a=0)

{c=c+1;

}

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}if (c=2)

printf("the given number is prime");else

printf("the given number is not prime");

}

Answer by SATINDRA MOHAN

Submitted on 7/19/2006

Rating: Not yet rated Rate this answer:

main(){int a,c=1,i,n;printf(" NUMBER = ");scanf("%d",&n);for(i=1;i<=n;i++)

{a=n%i;if(a==0)

{c=c+1;

}}

if (c==3)printf(" PRIME NUMBER");elseprintf(" NOT PRIME NUMBER");

getch();}

Answer by priya

Submitted on 7/23/2006

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4 IS NOT A PRIME

Answer by Sudhakar Desaboina

Submitted on 8/23/2006

Rating: Not yet rated Rate this answer:

main(){int a,c=0,i,n;printf("enter the number to be checked");

scanf("%d",&n);for(i=1;i<=n;i++){

a=n%i;if(a==0)

{c=c+1;

}}

if (c==2)printf("the given number is prime");

elseprintf("the given number is not prime");}

Answer by Santosh

Submitted on 8/31/2006

Rating: Not yet ratedRate this answer:

// program for finding prime number

#include<stdio.h>

int isPrime(int n){

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8/8/2019 Program to Find a Prime Number

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int i,j;i=1;

j=0;while(i<=n){

if(n%i==0) j++;

i++;}if(j==2){

printf("Prime");return 1;

}else{

printf("Not Prime");return 1;

}}int main(){

int num;printf("Enter Number : ");scanf("%d",&num);isPrime(num);return 1;

}

Answer by sumanth

Submitted on 11/10/2006

Rating: Not yet rated Rate this answer:

main(){int a,c=0,i,n;printf("enter the number to be checked");scanf("%d",&n);for(i=1;i<=n;i++)

{a=n%i;

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if(a==0){

c=c+1;}

}

if (c==2){ printf("the given number is prime"); }

elseprintf("the given number is not prime");

}

Answer by neeraj

Submitted on 11/11/2006

Rating: Not yet rated Rate this answer:

main(){int a,c=0,i,n;printf("enter the number to be checked");scanf("%d",&n);for(i=1;i<=n;i++)

{a=n%i;if(a==0)

{c=c+1;

}}

if (c==2){ printf("the given number is prime"); }

elseprintf("the given number is not prime");

}

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Answer by sundar

Submitted on 12/29/2006

Rating: Not yet rated Rate this answer:

#include <stdio.h>main (){

int i, j, prime = 0;for (i = 1; i < 1000; i++)

{prime = 0;for (j = 2; j < (i / 2) + 1; j++)

{if (i % j == 0)

{

prime = 1;break;

}}

if (prime == 0){

printf ("%d is a prime number\n", i);}

}}

Answer by Shiwani

Submitted on 1/14/2007

Rating: Not yet rated Rate this answer:

main(){

int i,n,rem,sq;

printf("enter the number to be checked");scanf("%d"&n);sq=sqrt(n);for(i=2,i<=sq,i++)do{

rem=n%i;if(rem==0)

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8/8/2019 Program to Find a Prime Number

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{printf("given number is not prime");exit;

}}

printf("given number is prime");}

Answer by Arjun

Submitted on 1/23/2007

Rating: Not yet rated Rate this answer:

int main (){int r,n;printf("Enter a number to be checked : ");scanf("%d",&n);for(r=2;r<=n;r++){if(n%r==0){

if(r < n){printf("It is not a prime number\n");break;}elseprintf("It is a prime number\n");}}}

Answer by fearfact_53

Submitted on 2/9/2007

Rating: Not yet rated Rate this answer:

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8/8/2019 Program to Find a Prime Number

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This program runs, if you enter a add number that is not prime it will tell youthat it is a prime number. Any way nice try. Email me if you want 1 thatworks. ( fearfact_53@yahoo.com)

Answer by KDW

Submitted on 2/19/2007

Rating: Not yet rated Rate this answer:

// This program determines the nearest prime numbers // Written in C++ // By: KDW // Febuary 1, 2007

// Several revisions are included in this edition /*1. As soon as a remainder of 0 is encountered theprogram moves on to the next incremented value aboveor below the seed.2. When testing whether a particular seed is a primethe program only test up to 1/2 of the seed value.3. Displays how many iterations were needed to producethe result.

*/

#include <iostream>using namespace std;

int main(){

long seed, seed2, seed3, pnum, dnum, rem, counter, counter2;bool prime, prime2;

// Let the user test multiple valuesfor (seed3 = -1; seed3 != 0; ){

counter = counter2 = 1;if(seed3 >= 0)seed = seed3;

else{cout << "Enter a number and I will tell\n"

<< "you it's nearest prime number.\n";cin >> seed;}

// Prevent the user from entering a negative number

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while (seed <= 0){

cout << "Please enter a valid number (greater than 0)!\n";cin >> seed ;

}

// Automatically says user's value is prime if they enter 1if (seed == 1)

cout << seed << " is the smallest prime number!\n"<< "2 is the nearest larger prime number!\n";

else if (seed == 2)cout << seed << " is a prime number!\n";

else{seed2 = seed ; // Defines the seed number for the smaller primes

// Finds the nearest lager prime

for (prime = 0 ; prime != 1 ; seed++){

// Tests whether number is a primednum = 2 ;rem = seed % dnum ;if (rem == 0)

prime = 0;else{

for (pnum = seed, dnum = 3, prime = 1 ; dnum <= (pnum / 2) &&prime != 0; dnum += 2)

{rem = pnum % dnum ;if (rem == 0)

prime = 0;counter++;

}}

} // Finds the nearest smaller prime

for (prime2 = 0 ; prime2 != 1 ; seed2--){

// Tests whether number is a primednum = 2 ;rem = seed2 % dnum ;if (rem == 0)

prime2 = 0;else{

for (pnum = seed2, dnum = 3, prime2 = 1 ; dnum <= (pnum / 2) &&

8/8/2019 Program to Find a Prime Number

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prime2 != 0 ; dnum += 2){

rem = pnum % dnum ;if (rem == 0)

prime2 = 0;

counter2++ ;}

}}

cout << --seed << " is the nearest larger prime number!\n";cout << ++seed2 << " is the nearest smaller prime number!\n";cout << counter + counter2 << " calculations";}cout << "\nEnter another number (type '0' to quit)\n" ;cin >> seed3;cout << endl;

}return 0;

}

Answer by kiran vellanki

Submitted on 3/27/2007

Rating: Not yet rated Rate this answer:

int main(){int a,b,c,d=0;printf("Enter the number : ");scanf("%d",&a);c=a/2;

for(b=2;b<=c;b++){if (a%b==0)

++d;}

if (d==0 && a>0)printf("\n\nThe number is prime");elseprintf("\n\nThe number is not prime");

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clrscr();printf("Enter Number Of Terms

");printf("Prime Numbers Are Follwing

");

scanf("%d",&n);while(i<=n){

c=0;for(j=1;j<=i;j++){

if(i%j==0)c++;

}if(c==2)printf("%d ",i)

i++;}getch();

}

Answer by Waleed

Submitted on 6/24/2007

Rating: Not yet rated Rate this answer:

Not really..

if(a=0)

if (c=2)

will always be true...

CORRECTION::

if (a==0)

if (c==0)

After doing the correction.. the program seems to work..

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