C语言的优先级和结合律？

cozim 2012-10-07 06:05:37

x+++y;
这个表达式的优先级，结合律是什么？

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zhcosin 2012-10-09

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纠结这干啥，语法都是编译器定的，如果你有足够的水平，自己写两个解释器按照两种思路去解释它，你说哪个正确？
有空纠结这个，还不如自己实现个小型编译器，你就知道其实这些都是编译器定的。

bravery36 2012-10-09

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蛋疼日经贴，明明都置顶了还有。

_暮落_ 2012-10-09

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何必记规律用到的时候直接加括号清晰明了不容易出错还好用
在调试的时候就显示出来你的优势了

lin5161678 2012-10-09

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[Quote=引用 27 楼的回复:]
没有任何学的必要，这种垃圾代码我完全没有兴趣。钻究这种无意义小道为的是什么？
[/Quote]

不是学写这种代码我去这代码我也鄙视
而是学习分辨什么的未定义行为什么不是
然后你才能避免无意中写出包含未定义行为的代码

赵4老师 2012-10-09

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// C++ Operator Precedence and Associativity

// The highest precedence level is at the top of the table.

//+------------------+-----------------------------------------+---------------+

//| Operator         | Name or Meaning                         | Associativity |

//+------------------+-----------------------------------------+---------------+

//| ::               | Scope resolution                        | None          |

//| ::               | Global                                  | None          |

//| [ ]              | Array subscript                         | Left to right |

//| ( )              | Function call                           | Left to right |

//| ( )              | Conversion                              | None          |

//| .                | Member selection (object)               | Left to right |

//| ->               | Member selection (pointer)              | Left to right |

//| ++               | Postfix increment                       | None          |

//| --               | Postfix decrement                       | None          |

//| new              | Allocate object                         | None          |

//| delete           | Deallocate object                       | None          |

//| delete[ ]        | Deallocate object                       | None          |

//| ++               | Prefix increment                        | None          |

//| --               | Prefix decrement                        | None          |

//| *                | Dereference                             | None          |

//| &                | Address-of                              | None          |

//| +                | Unary plus                              | None          |

//| -                | Arithmetic negation (unary)             | None          |

//| !                | Logical NOT                             | None          |

//| ~                | Bitwise complement                      | None          |

//| sizeof           | Size of object                          | None          |

//| sizeof ( )       | Size of type                            | None          |

//| typeid( )        | type name                               | None          |

//| (type)           | Type cast (conversion)                  | Right to left |

//| const_cast       | Type cast (conversion)                  | None          |

//| dynamic_cast     | Type cast (conversion)                  | None          |

//| reinterpret_cast | Type cast (conversion)                  | None          |

//| static_cast      | Type cast (conversion)                  | None          |

//| .*               | Apply pointer to class member (objects) | Left to right |

//| ->*              | Dereference pointer to class member     | Left to right |

//| *                | Multiplication                          | Left to right |

//| /                | Division                                | Left to right |

//| %                | Remainder (modulus)                     | Left to right |

//| +                | Addition                                | Left to right |

//| -                | Subtraction                             | Left to right |

//| <<               | Left shift                              | Left to right |

//| >>               | Right shift                             | Left to right |

//| <                | Less than                               | Left to right |

//| >                | Greater than                            | Left to right |

//| <=               | Less than or equal to                   | Left to right |

//| >=               | Greater than or equal to                | Left to right |

//| ==               | Equality                                | Left to right |

//| !=               | Inequality                              | Left to right |

//| &                | Bitwise AND                             | Left to right |

//| ^                | Bitwise exclusive OR                    | Left to right |

//| |                | Bitwise OR                              | Left to right |

//| &&               | Logical AND                             | Left to right |

//| ||               | Logical OR                              | Left to right |

//| e1?e2:e3         | Conditional                             | Right to left |

//| =                | Assignment                              | Right to left |

//| *=               | Multiplication assignment               | Right to left |

//| /=               | Division assignment                     | Right to left |

//| %=               | Modulus assignment                      | Right to left |

//| +=               | Addition assignment                     | Right to left |

//| -=               | Subtraction assignment                  | Right to left |

//| <<=              | Left-shift assignment                   | Right to left |

//| >>=              | Right-shift assignment                  | Right to left |

//| &=               | Bitwise AND assignment                  | Right to left |

//| |=               | Bitwise inclusive OR assignment         | Right to left |

//| ^=               | Bitwise exclusive OR assignment         | Right to left |

//| ,                | Comma                                   | Left to right |

//+------------------+-----------------------------------------+---------------+