# | - bitwise OR

suggest change
``````#include <iostream>
#include <string>

int main(int argc, char **argv) {
int a = 5;     // 0101b  (0x05)
int b = 12;    // 1100b  (0x0C)
int c = a | b; // 1101b  (0x0D)

std::cout << "a = " << a << ", b = " << b << ", c = " << c << std::endl;
}``````
``````a = 5, b = 12, c = 13
``````

Why

A bit wise `OR` operates on the bit level and uses the following Boolean truth table:

``````true OR true = true
true OR false = true
false OR false = false``````

When the binary value for `a` (`0101`) and the binary value for `b` (`1100`) are `OR`’ed together we get the binary value of `1101`:

``````int a = 0 1 0 1
int b = 1 1 0 0 |
---------
int c = 1 1 0 1``````

The bit wise OR does not change the value of the original values unless specifically assigned to using the bit wise assignment compound operator `|=`:

``````#include <iostream>
#include <string>

int main(int argc, char **argv) {
int a = 5;  // 0101b  (0x05)
a |= 12;    // a = 0101b | 1101b == 13

std::cout << "a = " << a << std::endl;
}``````
``````a = 13
``````