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for(int x = 0 , y = 0; !x && y

[单选题]

for(int x = 0 , y = 0; !x && y <= 5 ; y++)

语句执行循环的次数是多少次？

```
0
```
```
5
```
```
6
```
```
无数次
```

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小海豹

如果循环体中X得值不改变，!x一直为true，则只需要考虑y的值就可以了，一共6次。

编辑于 2015-02-07 16:45:00 回复(0)

青山崖野

算数运算符>关系运算符>&&>||>赋值运算符

y = 0; !x && y <= 5 就是 (!x) && (y <= 5)

发表于 2017-04-17 21:25:42 回复(0)

文中序

这里有个坑，x是不会变的，始终为0

发表于 2017-06-15 09:45:01 回复(3)

XiuCai

选C. 关键在于判断表达式的执行顺序: (!x)&&(y<=5)。(!x)一直为true，相当于只有(y<=5)这一个条件。

发表于 2018-12-12 14:24:22 回复(0)

seaway

Precedence	Operator	Description	Example	Associativity
1	() [] -> . :: ++ --	Grouping operator Array access Member access from a pointer Member access from an object Scoping operator Post-increment Post-decrement	(a + b) / 4; array[4] = 2; ptr->age = 34; obj.age = 34; Class::age = 2; for( i = 0; i < 10; i++ ) ... for( i = 10; i > 0; i-- ) ...	left to right
2	! ~ ++ -- - + * & (type) sizeof	Logical negation Bitwise complement Pre-increment Pre-decrement Unary minus Unary plus Dereference Address of Cast to a given type Return size in bytes	if( !done ) ... flags = ~flags; for( i = 0; i < 10; ++i ) ... for( i = 10; i > 0; --i ) ... int i = -1; int i = +1; data = *ptr; address = &obj; int i = (int) floatNum; int size = sizeof(floatNum);	right to left
3	->* .*	Member pointer selector Member pointer selector	ptr->var = 24; obj.var = 24;	left to right
4	* / %	Multiplication Division Modulus	int i = 2 * 4; float f = 10 / 3; int rem = 4 % 3;	left to right
5	+ -	Addition Subtraction	int i = 2 + 3; int i = 5 - 1;	left to right
6	<< >>	Bitwise shift left Bitwise shift right	int flags = 33 << 1; int flags = 33 >> 1;	left to right
7	< <= > >=	Comparison less-than Comparison less-than-or-equal-to Comparison greater-than Comparison geater-than-or-equal-to	if( i < 42 ) ... if( i <= 42 ) ... if( i > 42 ) ... if( i >= 42 ) ...	left to right
8	== !=	Comparison equal-to Comparison not-equal-to	if( i == 42 ) ... if( i != 42 ) ...	left to right
9	&	Bitwise AND	flags = flags & 42;	left to right
10	^	Bitwise exclusive OR	flags = flags ^ 42;	left to right
11	\|	Bitwise inclusive (normal) OR	flags = flags \| 42;	left to right
12	&&	Logical AND	if( conditionA && conditionB ) ...	left to right
13	\|\|	Logical OR	if( conditionA \|\| conditionB ) ...	left to right
14	? :	Ternary conditional (if-then-else)	int i = (a > b) ? a : b;	right to left
15	= += -= *= /= %= &= ^= \|= <<= >>=	Assignment operator Increment and assign Decrement and assign Multiply and assign Divide and assign Modulo and assign Bitwise AND and assign Bitwise exclusive OR and assign Bitwise inclusive (normal) OR and assign Bitwise shift left and assign Bitwise shift right and assign	int a = b; a += 3; b -= 4; a *= 5; a /= 2; a %= 3; flags &= new_flags; flags ^= new_flags; flags \|= new_flags; flags <<= 2; flags >>= 2;	right to left
16	,	Sequential evaluation operator	for( i = 0, j = 0; i < 10; i++, j++ ) ...	left to right