!Boolean Operators 

These can be used inside the condition of an [[arduino:control structures:If]] statement.

=====&& (logical and)   =====
True only if both operands are true, e.g.
<code arduino>
if (digitalRead(2) == HIGH  && digitalRead(3) == HIGH) { // read two switches 
  // ...
} </code>
is true only if both inputs are high.

=====|| (logical or)   =====
True if either operand is true, e.g.
<code arduino>
if (x > 0 || y > 0) {
  // ...
} </code>
is true if either x or y is greater than 0.

===== ! (not)   =====
True if the operand is false, e.g.
<code arduino>
if (!x) { 
  // ...
} </code>
is true if x is false (i.e. if x equals 0).

====Warning   ====
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.

====Examples   ====

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

====See also   ====

* [[arduino:bitwise operators:BitwiseAnd | &]] (bitwise AND)
* [[arduino:bitwise operators:BitwiseAnd | |]] (bitwise OR)
* [[arduino:bitwise operators:BitwiseXorNot | ~]] (bitwise NOT
* [[arduino:control structures:If]]




Source: arduino.cc