使用位運算符，這樣做的目的是為了節約內存開銷和加快計算效率

關于位運算符的兩個例子。

判斷一個整數是否是奇數

public class MainDemo {

    public static void main(String[] args) {
        // 測試
        if (isOddNumber5(-7)) {
            System.out.println("奇數");
        } else {
            System.out.println("偶數");
        }
    }

    /**
     * 該解法沒有考慮到負數
     * @param number
     * @return
     */
    public static Boolean isOddNumber(int number) {
        return number % 2 == 1;
    }

    /**
     * 把負數考慮進去
     * @param number
     * @return
     */
    public static Boolean isOddNumber2(int number) {
        return number % 2 == 1 || number % 2 == -1;
    }

    /**
     * 逆向思維
     * @param number
     * @return
     */
    public static Boolean isOddNumber3(int number) {
        return number % 2 != 0;
    }

    /**
     * 位運算符 移位
     * @param number
     * @return
     */
    public static Boolean isOddNumber4(int number) {
        return number >> 1 << 1 != number;
    }

    /**
     *  位運算符 與運算
     * @param number
     * @return
     */
    public static Boolean isOddNumber5(int number) {
        return (number & 1) == 1;
    }
}

請實現兩個整數變量的交換

    public static void main(String[] args) {

        int a = 3;
        int b = 5;

        /**
         * 添加變量temp
         */
        System.out.println(a + " " + b);
        int temp = a;
        a = b;
        b = temp;
        System.out.println(a + " " + b);

        /**
         * 相加
         */
        System.out.println(a + " " + b);
        a = a + b;
        b = a - b;
        a = a - b;
        System.out.println(a + " " + b);

        /**
         * 位運算符，一個數據針對另一個數據位異或兩次，該數不變
         */
        System.out.println(a + " " + b);
        a = a ^ b;
        b = a ^ b;
        a = a ^ b;
        System.out.println(a + " " + b);

        /**
         * 加法
         */
        System.out.println(a + " " + b);
        a = (a + b) - (b = a);
        System.out.println(a + " " + b);
    }