-
int x = 0; if (x = 0 || x == 0) printf("%dn", x); printf("%dn", x); - 參考C的優先表, 其實就是if (x = (0 || x == 0))
會printf出兩個1.
同一优先级的运算符，运算次序由结合方向所决定。简单记就是：！ > 算术运算符 > 关系运算符 > && > || > 赋值运算符
C Operator Precedence Table
This page lists C operators in order of precedence (highest to lowest). Their associativity indicates in what order operators of equal precedence in an expression are applied.
OperatorDescription
Associativity( )
[ ]
.
->
++ --Parentheses (function call) (see Note 1)
Brackets (array subscript)
Member selection via object name
Member selection via pointer
Postfix increment/decrement (see Note 2)
left-to-right++ --
+ -
! ~
(type)
*
&
sizeofPrefix increment/decrement
Unary plus/minus
Logical negation/bitwise complement
Cast (convert value to temporary value of type)
Dereference
Address (of operand)
Determine size in bytes on this implementationright-to-left * / % Multiplication/division/modulus left-to-right + - Addition/subtraction left-to-right << >> Bitwise shift left, Bitwise shift right left-to-right < <=
> >=Relational less than/less than or equal to
Relational greater than/greater than or equal toleft-to-right == != Relational is equal to/is not equal to left-to-right & Bitwise AND left-to-right ^ Bitwise exclusive OR left-to-right | Bitwise inclusive OR left-to-right && Logical AND left-to-right | | Logical OR left-to-right ? : Ternary conditional right-to-left =
+= -=
*= /=
%= &=
^= |=
<<= >>=Assignment
Addition/subtraction assignment
Multiplication/division assignment
Modulus/bitwise AND assignment
Bitwise exclusive/inclusive OR assignment
Bitwise shift left/right assignmentright-to-left
,Comma (separate expressions) left-to-right - Note 1:
- Parentheses are also used to group sub-expressions to force a different precedence; such parenthetical expressions can be nested and are evaluated from inner to outer.
- Note 2:
- Postfix increment/decrement have high precedence, but the actual increment or decrement of the operand is delayed (to be accomplished sometime before the statement completes execution). So in the statement y = x * z++; the current value of z is used to evaluate the expression (i.e., z++ evaluates to z) and z only incremented after all else is done. See postinc.c for another example.
时间： 2024-08-28 12:26:34