The bitwise OR operator in C++ is the vertical bar symbol, |. Like the & operator, | operates independently each bit in its two surrounding integer expressions, but what it does is different (of course). The bitwise OR of two bits is 1 if either or both of the input bits is 1, otherwise it is 0. In other words:
0 0 1 1 operand1 0 1 0 1 operand2 ---------- 0 1 1 1 (operand1 | operand2) - returned result
Here is an example of the bitwise OR used in a snippet of C++ code:
int a = 92; // in binary: 00000000000000000000000001011100 int b = 101; // in binary: 00000000000000000000000001100101 int c = a | b; // result: 00000000000000000000000001111101, or 125 in decimal.
One of the most common uses of the Bitwise OR is to set multiple bits in a bit-packed number.
// Note: This code is AVR architecture specific // set direction bits for pins 2 to 7, leave PD0 and PD1 untouched (xx | 00 == xx) // same as pinMode(pin, OUTPUT) for pins 2 to 7 on Uno or Nano DDRD = DDRD | 0b11111100;
- [程式語法] || Logical OR
- [Example] BitMath Tutorial
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