C language operator priority, operator priority

C language operator priority, operator priority

 

Priority	Operator	Name or meaning	Usage	Integration direction	Description
1	[]	Array subscript	Array name [constant expression]	Left to right	--
	()	Parentheses	(Expression)/function name (parameter table)		--
	.	Member selection (object)	Object. member name		--
	->	Member selection (pointer)	Object Pointer-> member name		--
2	-	Negative Operator	-Expression	Right to left	Single Object Operator
	~	Bitwise Inverse Operator	~ Expression
	++	Auto-increment operator	++ Variable name/variable name ++
	--	Auto-subtraction Operator	-- Variable name/variable name --
	*	Value Operator	* Pointer variable
	&	Bitwise operators	& Variable name
	!	Logical non-Operator	! Expression
	(Type)	Forced type conversion	(Data Type) Expression		--
	Sizeof	Length Operator	Sizeof (expression)		--
3	/	Division	Expressions/Expressions	Left to right	Binary Operators
	*	Multiplication	Expression * Expression
	%	Remainder (Modulo)	Integer expression % integer expression
4	+	Add	Expression + expression	Left to right	Binary Operators
	-	Subtraction	Expression-expression
5	<	Move left	Variable <expression	Left to right	Binary Operators
	>	Right Shift	Variable> Expression
6	>	Greater	Expression> Expression	Left to right	Binary Operators
	> =	Greater than or equal	Expression> = expression
	<	Less	Expression <expression
	<=	Less than or equal	Expression <= expression
7	=	Equal	Expression = expression	Left to right	Binary Operators
	! =	Not equal	Expression! = Expression
8	&	Bitwise AND	Expressions & Expressions	Left to right	Binary Operators
9	^	Bitwise OR	Expression ^ expression	Left to right	Binary Operators
10	|	By bit or	Expression | expression	Left to right	Binary Operators
11	&&	Logic and	Expressions & Expressions	Left to right	Binary Operators
12	|	Logic or	Expression | expression	Left to right	Binary Operators
13	? :	Conditional Operators	Expression 1? Expression 2: expression 3	Right to left	Three-object Operator
14	=	Value assignment operator	Variable = expression	Right to left	--
	/=	Assignment After Division	Variable/= expression		--
	* =	Assign value after Multiplication	Variable * = expression		--
	% =	Assign value after modulo operation	Variable % = expression		--
	+ =	Add and assign values	Variable + = expression		--
	-=	Value after subtraction	Variable-= expression		--
	<=	Value after left shift	Variable <= expression		--
	>>=	Value after right shift	Variable> = expression		--
	& =	Bitwise AND postvalue	Variable & = expression		--
	^ =	Value Based on bitwise XOR	Variable ^ = expression		--
	| =	Value by bit or after	Variable | = expression		--
15	,	Comma Operator	Expressions, expressions ,...	Left to right	--

Note:
For operators with the same priority, the operation order is determined by the combination direction.
Note :! > Arithmetic Operators> Relational operators >&>||> value assignment operators

 

Char s [] = "012345678 ";

Char * p = s;

 

1. ++ * p: PPoint to S [0], and add S [0] and 1 as the expression value, so the output is 1. At this time, S [0] = '1'
2. ++ (* p): P also points to S [0] (S [0] The current value is 1), and adds S [0] and 1 as the expression value, so the output is 2. S [0] = '2'
3. * (++ p): p points to S [1], then takes the value of S [1] as the value of the expression, and outputs '1'
4. * ++ p: P points to S [2], then takes the value of S [2] As the expression value, and outputs '2'
5. (* p) ++: P still points to S [2]. Take the value of S [2] as the value of the expression, so '2' is output ', then the value of S [2] is added with 1, S [2] = 3
6. * (p ++): P still points to S [2] (present value is 3). Take the value of S [2] as the value of the expression, so output '3 ', then P points to S [3].
7. * p ++: P points to S [3] and takes the value of S [3] as the value of the expression. Therefore, output '3' and P points to S [4].

 

* P ++ extracts the value of * p first, and then asks p ++
(* P) ++ extracts the value of * p first, so that this value can be ++
* (P ++) is to extract the value of * p first, so that p ++
Therefore, * p ++ is equivalent to * (P ++)
In addition, printf runs from right to left. In addition, the right ++ operation is performed after the entire operation expression is completed, and the execution order of the right ++ operation is from left to right.

When the left ++ encounters a variable, it will immediately increase the value of the variable.