70,027
社区成员
发帖
与我相关
我的任务
分享C语言强制类型转换优先级问题，请高手解答，多谢啦。
小弟初学C语言，对于强制类型转化有一个小小的问题，还请大神们指点一二。
int a;
a = (int) father->age;
问题就在这里，里面的强制类型转化优先级是怎么算的？
我知道一般都是加括号，像是a = (int) （father->age）;但是不加括号，怎么运算的？
有些不明白，还请大婶们指教。
int a;
a = (int) father->age;
问题就在这里，里面的强制类型转化优先级是怎么算的？
我知道一般都是加括号，像是a = (int) （father->age）;但是不加括号，怎么运算的？
有些不明白，还请大婶们指教。
...全文
请发表友善的回复…
发表回复
米尼小邪 2014-08-18
- 打赏
- 举报
建议括号，代码风格问题~
ViewerP 2014-08-18
- 打赏
- 举报
建议楼主看看C语言运算符优先级表，那样就OK了
乌镇程序员 2014-08-13
- 打赏
- 举报
查一下运算符优先级表就知道了，成员选择运算符优先级高于强制类型转换，这里加不加括号没影响
liudiancun 2014-08-13
- 打赏
- 举报
大神们指点，不是大婶们。
赵4老师 2014-08-13
- 打赏
- 举报
//C++ Operators
// Operators specify an evaluation to be performed on one of the following:
// One operand (unary operator)
// Two operands (binary operator)
// Three operands (ternary operator)
// The C++ language includes all C operators and adds several new operators.
// Table 1.1 lists the operators available in Microsoft C++.
// Operators follow a strict precedence which defines the evaluation order of
//expressions containing these operators. Operators associate with either the
//expression on their left or the expression on their right; this is called
//“associativity.” Operators in the same group have equal precedence and are
//evaluated left to right in an expression unless explicitly forced by a pair of
//parentheses, ( ).
// Table 1.1 shows the precedence and associativity of C++ operators
// (from highest to lowest precedence).
//
//Table 1.1 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 |
//+------------------+-----------------------------------------+---------------+
taodm 2014-08-13
- 打赏
- 举报
加点括号不是很好的行为么。
liudiancun 2014-08-13
- 打赏
- 举报
多谢各位的指点啦。 不过我说的C语言中的优先级。不过，我明白了， 多谢各位啦。
jlfzhz 2014-08-13
- 打赏
- 举报
[quote=引用 楼主 liudiancun 的回复:]
小弟初学C语言，对于强制类型转化有一个小小的问题，还请大神们指点一二。
int a;
a = (int) father->age;
问题就在这里，里面的强制类型转化优先级是怎么算的？
我知道一般都是加括号，像是a = (int) （father->age）;但是不加括号，等同于 a=(int) (father->age),
解释见楼上
ViewerP 2014-08-13
- 打赏
- 举报
结构有类型么？将结构强制转换有什么意义么？或者说，你使用的指向结构的指针，那是一个地址；所以，强制转换的对象是结构的成员。可以将father->age看作一个整体，相当于你在main中定义的一个float类型变量，然后将这个变量进行强制转换为int类型
神奕 2014-08-13
- 打赏
- 举报
成员访问运算符->的优先级高于强制类型转换运算符(type)。
C++ 运算符优先级列表：http://www.cppblog.com/aqazero/archive/2012/11/10/8284.html
