How to check prime number of a given number?

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Check prime number of a given number

Here’s an example Java program to check if a given number is prime or not:

import java.util.Scanner;

public class PrimeChecker {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter a number: ");
        int number = sc.nextInt();
        boolean isPrime = true;
        
        if (number < 2) {
            isPrime = false;
        } else {
            for (int i = 2; i <= Math.sqrt(number); i++) {
                if (number % i == 0) {
                    isPrime = false;
                    break;
                }
            }
        }
        
        if (isPrime) {
            System.out.println(number + " is a prime number.");
        } else {
            System.out.println(number + " is not a prime number.");
        }
    }
}

The program asks the user to enter a number, and then it checks whether the number is prime or not using a for loop that iterates from 2 to the square root of the number. If the number is divisible by any of the integers in that range, then it is not a prime number. If the number is not divisible by any of the integers in that range, then it is a prime number. The program then prints out a message indicating whether the number is prime or not.