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Program to Print First n Prime Numbers using While loop

Program to Print First n Prime Numbers using While loop

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  • Write a program to Print First n Prime Numbers using While loop in C
  • Write a program to Print First n Prime Numbers using While loop in C++
  • Write a program to Print First n Prime Numbers using While loop in Python
  • Write a program to Print First n Prime Numbers using While loop in PHP
  • Write a program to Print First n Prime Numbers using While loop in Java
  • Write a program to Print First n Prime Numbers using While loop in Java Script
  • Write a program to Print First n Prime Numbers using While loop in C#

Explanation:

To print the first n prime numbers using a While loop, we need to:

Steps:

  • Take input for n (the number of prime numbers to print).
  • Prime number check: To check if a number i is prime:
  • A number is prime if it is greater than 1 and divisible only by 1 and itself.
  • For each candidate number, check if it is divisible by any number from 2 to sqrt(i).
  • Loop to print the first n prime numbers:
  • Start from 2 and continue until we find n prime numbers.


Logic:

  • Iterate through numbers starting from 2 (the smallest prime number).
  • For each number, check if it is prime.
  • If it is prime, print it and count the prime numbers printed so far.
  • Stop when n prime numbers are found.

Explanation:

  • For input n = 5:
  • The program starts checking numbers from 2 (the first prime number).
  • It checks each number to see if it is prime and prints it.
  • The first 5 prime numbers are 2, 3, 5, 7, and 11

Optimization Note:

  • By checking divisibility only up to sqrt(num), the program reduces unnecessary checks for larger divisors and increases efficiency.

Program to Print First n Prime Numbers using While loop

#include <stdio.h>

int main() {
    int n, num = 2, count = 0;

    printf("Enter how many prime numbers to print: ");
    scanf("%d", &n);

    printf("First %d prime numbers are: ", n);

    // Print the first n prime numbers using a while loop
    while (count < n) {
        int isPrime = 1;
        for (int i = 2; i <= num / 2; i++) {
            if (num % i == 0) {
                isPrime = 0;
                break;
            }
        }
        if (isPrime) {
            printf("%d ", num);
            count++;
        }
        num++;
    }

    return 0;
}

#include <iostream>
using namespace std;

int main() {
    int n, num = 2, count = 0;

    cout << "Enter how many prime numbers to print: ";
    cin >> n;

    cout << "First " << n << " prime numbers are: ";

    // Print the first n prime numbers using a while loop
    while (count < n) {
        bool isPrime = true;
        for (int i = 2; i <= num / 2; i++) {
            if (num % i == 0) {
                isPrime = false;
                break;
            }
        }
        if (isPrime) {
            cout << num << " ";
            count++;
        }
        num++;
    }

    return 0;
}

n = int(input("Enter how many prime numbers to print: "))
num = 2
count = 0

print(f"First {n} prime numbers are: ", end="")

# Print the first n prime numbers using a while loop
while count < n:
    is_prime = True
    for i in range(2, num // 2 + 1):
        if num % i == 0:
            is_prime = False
            break
    if is_prime:
        print(num, end=" ")
        count += 1
    num += 1


<?php
$n = (int)readline("Enter how many prime numbers to print: ");
$num = 2;
$count = 0;

echo "First $n prime numbers are: ";

# Print the first n prime numbers using a while loop
while ($count < $n) {
    $isPrime = true;
    for ($i = 2; $i <= $num / 2; $i++) {
        if ($num % $i == 0) {
            $isPrime = false;
            break;
        }
    }
    if ($isPrime) {
        echo "$num ";
        $count++;
    }
    $num++;
}
?>


import java.util.Scanner;

public class PrimeNumbers {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        System.out.print("Enter how many prime numbers to print: ");
        int n = sc.nextInt();
        int num = 2, count = 0;

        System.out.print("First " + n + " prime numbers are: ");

        // Print the first n prime numbers using a while loop
        while (count < n) {
            boolean isPrime = true;
            for (int i = 2; i <= num / 2; i++) {
                if (num % i == 0) {
                    isPrime = false;
                    break;
                }
            }
            if (isPrime) {
                System.out.print(num + " ");
                count++;
            }
            num++;
        }

        sc.close();
    }
}


let n = parseInt(prompt("Enter how many prime numbers to print: "));
let num = 2;
let count = 0;

console.log(`First ${n} prime numbers are:`);
while (count < n) {
    let isPrime = true;
    for (let i = 2; i <= num / 2; i++) {
        if (num % i === 0) {
            isPrime = false;
            break;
        }
    }
    if (isPrime) {
        console.log(num);
        count++;
    }
    num++;
}


using System;

class Program {
    static void Main() {
        Console.Write("Enter how many prime numbers to print: ");
        int n = int.Parse(Console.ReadLine());
        int num = 2, count = 0;

        Console.Write("First " + n + " prime numbers are: ");

        // Print the first n prime numbers using a while loop
        while (count < n) {
            bool isPrime = true;
            for (int i = 2; i <= num / 2; i++) {
                if (num % i == 0) {
                    isPrime = false;
                    break;
                }
            }
            if (isPrime) {
                Console.Write(num + " ");
                count++;
            }
            num++;
        }
    }
}

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