&&（短路與）與&的區別：

• 最終結果都是一樣的

• &&具有短路的效果。左邊是false，右邊就不執行

   例如：
    int x = 3;
    int y = 4;
    System.out.println((++x == 3) & (++y == 4)); //false & false = false
    System.out.println("x = " + x);     //x = 4
    System.out.println("y = " + y);     //y = 5
  
    System.out.println((++x == 3) && (++y == 4)); //false & false = false
    System.out.println("x = " + x);     //x = 5
    System.out.println("y = " + y);     //y = 5
   
  

||（短路或）與|的區別：

• 最終的效果都是一樣的

• ||具有短路的效果，左邊為true，右邊不執行

    int x = 3;
    int y = 4;
    System.out.println((++x == 3) | (++y == 4)); //false & false = false
    System.out.println("x = " + x);     //x = 4
    System.out.println("y = " + y);     //y = 5
  
    System.out.println((++x == 3) || (++y == 4)); //false & false = false
    System.out.println("x = " + x);     //x = 5
    System.out.println("y = " + y);     //y = 6