In this tutorial, we will write a program to check whether the number is prime or not in java. Before that, you should have knowledge on the following topic in java.
Prime Number
A number is said to be a prime number if it is divisible by itself and 1. Example: 3, 5, 7, 11, 13, 17, 19, etc.
Explanation:
We take a boolean variable isPrime and assigned it to be true. Then we take the user input and start a for loop for i = 2 end the loop for i less than half of the number entered. i will increase by 1 after each iteration.
Inside for loop, a temp variable will contain the remainder of each iteration. And then if statement will check for temp to be 0 that is if the remainder is zero, isPrime is set to false. If isPrime is true, the number is Prime number else not.
Java Program to check whether a Number is Prime or Not
source code: Java Program to check for the prime number.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 | //check for the prime Number import java.util.Scanner; public class PrimrNumberCheck { public static void main(String args[]) { int temp; boolean isPrime = true; Scanner scan = new Scanner(System.in); System.out.print("Enter any number: "); int num = scan.nextInt(); scan.close(); for (int i = 2; i <= num / 2; i++) { temp = num % i; if (temp == 0) { isPrime = false; break; } } if (isPrime) System.out.println(num + " is a Prime Number"); //If isPrime is true else System.out.println(num + " is not a Prime Number"); //If isPrime is false } } |
Output:
Enter any number: 13
13 is a Prime Number