PrimeNumberSnippet.java

/*
 * MIT License
 *
 * Copyright (c) 2017-2022 Ilkka Seppälä
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package math;

/**
 * PrimeNumberSnippet.
 */
public class PrimeNumberSnippet {

  /**
   * Checks if given number is a prime number. Prime number is a number that is greater than 1 and
   * divided by 1 or itself only Credits: https://en.wikipedia.org/wiki/Prime_number
   *
   * @param number number to check prime
   * @return true if prime
   */
  public static boolean isPrime(int number) {
    //if number < 2 its not a prime number
    if (number < 2) {
      return false;
    }
    // 2 and 3 are prime numbers
    if (number < 3) {
      return true;
    }
    // check if n is a multiple of 2
    if (number % 2 == 0) {
      return false;
    }
    // if not, then just check the odds
    for (var i = 3; i * i <= number; i += 2) {
      if (number % i == 0) {
        return false;
      }
    }
    return true;
  }
}