Java Ice Breakers

How to check whether a given integer is prime number or not

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by

anagendrakumar2020

in Java, Prime number

This is the second solution to find whether the given integer number is prime or not using a simple predicate and another core logic that no number is divisible by more than half of itself.

import java.util.Scanner;
import java.util.function.Predicate;

public class PrimeNumCheck {

	public static void main(String[] args) {

		System.out.println("OUTPUT:");
		Scanner inpNum= new Scanner(System.in);
		System.out.print("Enter an integer value for prime number check:");
		int actualNum=inpNum.nextInt();
		boolean isPrime=true;

		//Define a basic predicate which checks reminder value
		Predicate<Integer> reminderEqualsToZero = i -> (i==0);

		//Initialize the highest boundary in the for loop
		int upperBoundary = actualNum/2;
		for(int num=2;num<=upperBoundary;num++) {
			if (reminderEqualsToZero.test(actualNum%num)) {
				isPrime=false;
				System.out.println("The number "+ actualNum+ " is not prime");
				break;
			}                        
		}
		if (isPrime)
			System.out.println("The number "+ actualNum +" is prime");
		inpNum.close();
	}
}

OUTPUT:
Enter an integer value for prime number check:641
The number 641 is prime