“布尔运算符”的版本间的差异

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These can be used inside the condition of an [[If(条件判断语句) 和 比较运算符 | if]] statement.
 
These can be used inside the condition of an [[If(条件判断语句) 和 比较运算符 | if]] statement.
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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。
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<font color="orange" size="+1">'''&& (逻辑与)'''</font>
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True only if both operands are true, e.g.
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<pre style="color:dimgray">
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if (digitalRead(2) == HIGH  && digitalRead(3) == HIGH) { // read two switches
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  // ...
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}
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</pre>
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is true only if both inputs are high.
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<font color="orange" size="+1">'''|| (逻辑或)'''</font>
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True if either operand is true, e.g.
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<pre style="color:dimgray">
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if (x > 0 || y > 0) {
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  // ...
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}
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</pre>
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is true if either x or y is greater than 0.
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<font color="orange" size="+1">'''! (取反)'''</font>
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True if the operand is false, e.g.
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<pre style="color:dimgray">
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if (!x) {
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  // ...
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}
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</pre>
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is true if x is false (i.e. if x equals 0).
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<font color="darkorenge">'''警告：'''</font><br/>
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Make sure you don't mistake the boolean AND operator, && (double ampersand) for the bitwise AND operator & (single ampersand). They are entirely different beasts.
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Similarly, do not confuse the boolean || (double pipe) operator with the bitwise OR operator | (single pipe).
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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.
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<font color="orange" size="+1">'''示例'''</font>
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<pre style="color:dimgray">
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if (a >= 10 && a <= 20){}  // true if a is between 10 and 20
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</pre>
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----
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[[Arduino语法参考 | 返回Arduino语法参考列表]]
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更多建议和问题欢迎反馈至 [http://www.yfrobot.com YFRobot论坛]

2015年8月19日 (三) 14:36的最后版本

These can be used inside the condition of an if statement.

这些可以使用于 if 语句中的条件判断。


&& (逻辑与)


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

if (digitalRead(2) == HIGH  && digitalRead(3) == HIGH) { // read two switches 
  // ...
}

is true only if both inputs are high.


|| (逻辑或)


True if either operand is true, e.g. 

if (x > 0 || y > 0) {
  // ...
}

is true if either x or y is greater than 0.


! (取反)


True if the operand is false, e.g. 

if (!x) { 
  // ...
}

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


警告：


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.


示例 

if (a >= 10 && a <= 20){}   // true if a is between 10 and 20



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