user-0 提问: while（ch=getchar()!='#'）与while（（ch=getchar()）!='#'）有什么区别

回复:
user: user-1
content: 2楼正解。 优先级问题

user: user-2
content: 运算优先级不要依靠设定的来，还是要靠自己加括号，易读，不易出错，不需要去记忆各种优先级

user: user-3
content: 引用 楼主 qq_34921840 的回复:下面这两个程序运行结果不一样 为什么？ #include <stdio.h> void main() { 	int line,space,other; 	char ch; 	line=0; 	space=0; 	other=0; 	while(ch=getchar()!='#') 	{ 		if(ch==' ')  			space++; 		else 			if(ch=='\n') line++; 				else  					other++; 		 	} 	printf("%d %d %d\n",space,line,other); }   #include <stdio.h> void main() { 	int line,space,other; 	char ch; 	line=0; 	space=0; 	other=0; 	while(（ch=getchar()）!='#') 	{ 		if(ch==' ')  			space++; 		else 			if(ch=='\n') line++; 				else  					other++; 		 	} 	printf("%d %d %d\n",space,line,other); }  倾向6楼的建议，多加（）好处多。

user: user-4
content: 仅供参考：//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 | //+------------------+-----------------------------------------+---------------+

user: user-5
content: 运算符优先级的问题，如果不清楚的话，建议多使用括号

user: user-2
content: 楼上都给你说了，运算符优先级问题 所以写代码的时候，最好对于有多个运算符的增加括号明确运算顺序 不要交给默认的优先级 自己容易搞糊涂，别人读起来困难，出了问题也不好跟踪

user: user-6
content: 优先级问题，前者ch等于  (getchar()!='#') 的计算结果（0或1），后者是ch = getchar()， 并判断ch是否等于'#'

user: user-7
content: 前面的是将获取的字符先判断是否为字符#，然后在赋值给ch。 而后面的是先将获取的字符赋值给ch，在进行判断是否为字符#。只是!=和=的优先级的问题，你回去好好看下

user: user-8
content: 遇到疑惑，不清楚走向的，还是多加括号，这可是个好习惯哦，尤其在那一堆运算符大杂烩的地方

user: user-9
content: !=的优先级大于= 所以你如果不加上括号的话while（ch=getchar()!='#'） 就会先计算getchar()!='#'，然后再将结果赋给ch