不同階段判斷一個int類型是否爲奇數

package com.huangliwei.jdk.other;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.junit.Test;

public class Demo1 {

	private static final Logger LOG = LogManager.getFormatterLogger(Demo1.class);

	@Test
	public void isOddTest() {

		// 判斷一個int類型是否是奇數
		for (int i = -10; i < 10; i++) {
			LOG.debug("[%s--%s]", i, isOdd4(i));
		}
	}

	// 基礎版v1.0
	private void isOdd0(int a) {
		if (a % 2 == 1) {
			System.out.println("是奇數!");
		} else {
			System.out.println("是偶數!");
		}
	}

	// 基礎版v1.1
	private boolean isOdd1(int a) {
		if (a % 2 == 1) {
			return true;
		} else {
			return false;
		}
	}

	// bug修復版v1.2
	private boolean isOdd2(int a) {
		if (a % 2 == 1 || a % 2 == -1) {
			return true;
		} else {
			return false;
		}
	}

	// 重構版v1.3
	private boolean isOdd3(int a) {
		return a % 2 != 0;
	}

	// 最終版v2.0
	private boolean isOdd4(int a) {
		return (a & 1) == 1;
	}
}