Breaking News: Grepper is joining You.com. Read the official announcement!

Prime Number Checker

Add Answer

LOLMAN_KS answered on March 4, 2022 Popularity 7/10 Helpfulness 10/10

answer Prime Number Checker

related Prime Check

related Prime Number Checker

Prime Number Checker

Comment

/*
	C++ Prime Number Checker program by lolman_ks.
    This logic can be used to build this program in other languages also.
*/
/*
	Logic: Divide the number by all numbers less than half of the number to
    check. If it is divisible by any of them, return False.
*/

#include <iostream>
#include <cmath>
using namespace std;

bool isPrime(int number){
	if(number == 1) return false; //1 is neither prime nor composite.
  	else if(number < 1) return false;
  	/*
    	O is the 0th multiple of every number, x * 0 = 0. Therefore 0 is not
        prime.
        Any -ve number is also composite because it has at least 3 factors:
        Itself, 1 and -1.
    */
  	else if(number == 2) return true; //Only even prime number;
  
  	else{
    	for(int i = 0;i <= ceil(number / 2);++i){
        	if(number % i == 0) return false; //Check exact divisibility.
        }
      	return true; 
      	/*
        	Return true if the loop is not broken and the number is not exactly
            divisible by any number.
        */
    }
}

//Implementations of this function.\
//Check prime numbers upto a limit.

int main(){
	int limit;
  	cout << "Enter limit: ";cin >> limit;
  
  	for(int i = 0;i <= limit;++i){
		cout << i << ": " << isPrime(i) << endl;
	}
}

/*
	I hope my answers are useful to you, please promote them if they are.
    #lolman_ks.
*/

Popularity 7/10 Helpfulness 10/10 Language cpp

Source: Grepper

Tags: c++

Link to this answer
Share Copy Link

Contributed on Mar 04 2022

LOLMAN_KS

0 Answers Avg Quality 2/10

Closely Related Answers

Prime Check

Comment

bool isPrime(ll n)
{
    if (n <= 1) return false;
 
    for (int i = 2; i <= sqrt(n); i++){
        if (n % i == 0)  return false;
    }

    return true;
}

Popularity 2/10 Helpfulness 1/10 Language cpp

Source: Grepper

Tags: c++

Link to this answer
Share Copy Link

Contributed on Oct 03 2023

Shishir Bhuiyan

0 Answers Avg Quality 2/10

Prime Number Checker

Comment

public class PrimeNumberChecker {
    public static void main(String[] args) {
        int number = 29;
        if (isPrime(number)) {
            System.out.println(number + " is a prime number.");
        } else {
            System.out.println(number + " is not a prime number.");
        }
    }

    public static boolean isPrime(int number) {
        if (number <= 1) {
            return false;  // 1 and non-positive numbers are not prime
        }
        if (number <= 3) {
            return true;   // 2 and 3 are prime
        }
        if (number % 2 == 0 || number % 3 == 0) {
            return false;  // numbers divisible by 2 or 3 are not prime
        }

        // Check for prime using 6k +/- 1 rule for efficiency
        for (int i = 5; i * i <= number; i += 6) {
            if (number % i == 0 || number % (i + 2) == 0) {
                return false;
            }
        }

        return true;
    }
}

Popularity 2/10 Helpfulness 1/10 Language java

Source: chat.openai.com

Tags: java

Link to this answer
Share Copy Link

Contributed on Oct 22 2023

Precious Pollan

0 Answers Avg Quality 2/10

Prime Number Checker

Contents

More Related Answers

Prime Number Checker

Closely Related Answers

Prime Check

Prime Number Checker

Grepper

Documentation

Social

Legal

Contact

Oops, You will need to install Grepper and log-in to perform this action.