FactorialSnippet.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;

/**
 * FactorialSnippet.
 */
public class FactorialSnippet {

  /**
   * Factorial. Works only for small numbers
   *
   * @param number for which factorial is to be calculated for
   * @return factorial
   */
  public static int factorial(int number) {
    var result = 1;
    for (var factor = 2; factor <= number; factor++) {
      result *= factor;
    }
    return result;
  }

  /**
   * Factorial. Example of what the recursive implementation looks like.
   *
   * @param number for which factorial is to be calculated for
   * @return factorial
   */
  public static int recursiveFactorial(int number) {
    var initial = 0;
    if (number == initial) {
      return initial + 1;
    }
    return number * recursiveFactorial(number - 1);
  }
}