Check Prime Number in Java

Here you will learn and get the program code to Check Prime Number in Java programming.

A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself.

Example to Check Prime Number in Java

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

public class PrimeCheck{

public static void main(String[] args) throws IOException {

// Create BufferedReader object for input number

BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

System.out.print("Enter a number: ");

int number = Integer.parseInt(reader.readLine());

reader.close();

// Check if number is prime

int i;

for (i = 2; i * i <= number; i++) {

if (number % i == 0) {

break;

}

// Display result

if (i * i > number) {

System.out.println(number + " is a prime number.");

} else {

System.out.println(number + " is not a prime number.");

}

Output

C:\CodeRevise\java>javac PrimeCheck.java

C:\CodeRevise\java>java PrimeCheck
Enter a number: 12
12 is not a prime number.

C:\CodeRevise\java>java PrimeCheck
Enter a number: 7
7 is a prime number.