There is a somewhat unusual operator in C++ called bitwise EXCLUSIVE OR, also known as bitwise XOR. (In English this is usually pronounced "eks-or".) The bitwise XOR operator is written using the caret symbol ^. A bitwise XOR operation results in a 1 only if the input bits are different, else it results in a 0.
Precisely,
0 0 1 1 operand1 0 1 0 1 operand2 ---------- 0 1 1 0 (operand1 ^ operand2) - returned result
int x = 12; // binary: 1100
int y = 10; // binary: 1010
int z = x ^ y; // binary: 0110, or decimal 6The ^ operator is often used to toggle (i.e. change from 0 to 1, or 1 to 0) some of the bits in an integer expression. In a bitwise XOR operation if there is a 1 in the mask bit, that bit is inverted; if there is a 0, the bit is not inverted and stays the same.
// Note: This code uses registers specific to AVR microcontrollers (Uno, Nano, Leonardo, Mega, etc.)
// it will not compile for other architectures
void setup() {
DDRB = DDRB | 0b00100000; // set PB5 (pin 13 on Uno/Nano, pin 9 on Leonardo/Micro, pin 11 on Mega) as OUTPUT
Serial.begin(9600);
}
void loop() {
PORTB = PORTB ^ 0b00100000; // invert PB5, leave others untouched
delay(100);
}EXAMPLE BitMath Tutorial