查看布尔运算符的源代码

These can be used inside the condition of an [[If(条件判断语句) 和 比较运算符 | if]] statement.

这些可以使用于[[If(条件判断语句) 和 比较运算符 | if]] 语句中的条件判断。



<font color="orange" size="+1">'''&& (逻辑与)'''</font>


True only if both operands are true, e.g.

<pre style="color:dimgray">
if (digitalRead(2) == HIGH  && digitalRead(3) == HIGH) { // read two switches 
  // ...
} 
</pre>

is true only if both inputs are high.



<font color="orange" size="+1">'''|| (逻辑或)'''</font>


True if either operand is true, e.g.

<pre style="color:dimgray">
if (x > 0 || y > 0) {
  // ...
} 
</pre>
is true if either x or y is greater than 0.



<font color="orange" size="+1">'''! (取反)'''</font>


True if the operand is false, e.g.

<pre style="color:dimgray">
if (!x) { 
  // ...
} 
</pre>

is true if x is false (i.e. if x equals 0).


<font color="darkorenge">'''警告：'''</font><br/>


Make sure you don't mistake the boolean AND operator, && (double ampersand) for the bitwise AND operator & (single ampersand). They are entirely different beasts.


Similarly, do not confuse the boolean || (double pipe) operator with the bitwise OR operator | (single pipe).


The bitwise not ~ (tilde) looks much different than the boolean not ! (exclamation point or "bang" as the programmers say) but you still have to be sure which one you want where.



<font color="orange" size="+1">'''示例'''</font>

<pre style="color:dimgray">
if (a >= 10 && a <= 20){}   // true if a is between 10 and 20
</pre>


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