Boolean Operators
These can be used inside the condition of an if statement.
&& (logical and)
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.
|| (logical or)
True if either operand is true, e.g.
if (x > 0 || y > 0) { // ... }
is true if either x or y is greater than 0.
! (not)
True if the operand is false, e.g.
if (!x) { // ... }
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
if (a >= 10 && a <= 20){} // true if a is between 10 and 20
See also
- & (bitwise AND)
- | (bitwise OR)
- ~ (bitwise NOT)
- if
The text of the 86Duino reference is a modification of the Arduino reference, and is licensed under a Creative Commons Attribution-ShareAlike 3.0 License. Code samples in the reference are released into the public domain.