运算符优先级
================

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    .f {
        font-family: Menlo, 'Droid Sans Mono', Consolas, monospace;
        font-weight: bold;
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.. role:: f

.. table:: 运算符的优先级
  :align: center

  +------------------+------------------+------------------+
  |    优先级        |   运算符         |      描述        |
  +==================+==================+==================+
  |        0         |    :f:`::`       |  作用域运算符    |
  +------------------+------------------+------------------+
  |                  |    :f:`[]`       |     下标运算     |
  +                  +------------------+------------------+
  |                  |    :f:`()`       |       圆括号     |
  +                  +------------------+------------------+
  |                  |    :f:`->`       |     指向运算符   |
  +         1        +------------------+------------------+
  |                  |    :f:`.`        |     成员运算符   |
  +                  +------------------+------------------+
  |                  |    :f:`++`       |     自增（后缀） |
  +                  +------------------+------------------+
  |                  |    :f:`-\-`      |     自减（后缀） |
  +------------------+------------------+------------------+
  |                  |    :f:`!`        |     逻辑非       |
  +                  +------------------+------------------+
  |                  |     :f:`~`       |    按位反        |
  +                  +------------------+------------------+
  |                  |    :f:`++`       |   自增（前缀）   |
  +                  +------------------+------------------+
  |                  |    :f:`-\-`      |    自减（前缀）  |
  +                  +------------------+------------------+
  |                  |    :f:`-`        |      负号        |
  +         2        +------------------+------------------+
  |                  |    :f:`+`        |      正号        |
  +                  +------------------+------------------+
  |                  |    :f:`(类型)`   |    类型转换      |
  +                  +------------------+------------------+
  |                  |    :f:`*`        |   指针运算符     |
  +                  +------------------+------------------+
  |                  |    :f:`&`        |   取地址         |
  +                  +------------------+------------------+
  |                  |    :f:`sizeof`   |    长度运算      |
  +------------------+------------------+------------------+
  |                  |    :f:`*`        |     乘法         |
  +                  +------------------+------------------+
  |        3         |    :f:`/`        |     除法         |
  +                  +------------------+------------------+
  |                  |    :f:`%`        |     求余         |
  +------------------+------------------+------------------+
  |                  |    :f:`+`        |     加法         |
  +        4         +------------------+------------------+
  |                  |    :f:`-`        |     减法         |
  +------------------+------------------+------------------+
  |                  |    :f:`<<`       |     左移位       |
  +        5         +------------------+------------------+
  |                  |   :f:`>>`        |     右移位       |
  +------------------+------------------+------------------+
  |        6         |  :f:`< <= > >=`  |    关系运算符    |
  +------------------+------------------+------------------+
  |                  |    :f:`==`       |    等于          |
  +        7         +------------------+------------------+
  |                  |    :f:`!=`       |    不等于        |
  +------------------+------------------+------------------+
  |        8         |    :f:`&`        |     按位与       |
  +------------------+------------------+------------------+
  |        9         |   :f:`^`         |    按位异或      |
  +------------------+------------------+------------------+
  |        10        |    :f:`|`        |    按位或        |
  +------------------+------------------+------------------+
  |        11        |    :f:`&&`       |    逻辑与        |
  +------------------+------------------+------------------+
  |        12        |    :f:`||`       |     逻辑或       |
  +------------------+------------------+------------------+
  |        13        |    :f:`? :`      |  条件运算符      |
  +------------------+------------------+------------------+
  |                  | :f:`=  += -= *=` |                  |
  +                  +                  +                  |
  |        14        | :f:`/= %= &= |=` |     赋值运算符   |
  +                  +                  +                  |
  |                  | :f:`^= <<= >>=`  |                  |
  +------------------+------------------+------------------+
  |        15        |   :f:`,`         |  逗号运算符      |
  +------------------+------------------+------------------+


.. note::

  位运算的优先级是：``~`` > ``&`` > ``^`` > ``|`` 。

  逻辑运算的优先级是：``!`` > ``&&`` > ``||`` 。

  不能重载的运算符：``.`` ，``? :`` ，``sizeof`` ，``.*`` ， ``::``。

  逻辑与：``exp1 && exp2`` ，如果 ``exp1`` 值为 0，则不对 ``exp2`` 求值。

  逻辑或：``exp1 || exp2`` ，如果 ``exp1`` 值为 1，则不对 ``exp2`` 求值。


参考资料
---------

1. Operator Overloading

  https://isocpp.org/wiki/faq/operator-overloading