expression   
|  
 expression  
  

The bitwise inclusive OR operator (|) compares each bit of its first operand to the corresponding bit of its second operand. If either bit is 1, the corresponding result bit is set to 1. Otherwise, the corresponding result bit is set to 0.

Both operands to the bitwise inclusive OR operator must be of integral types. The usual arithmetic conversions covered in Standard Conversions are applied to the operands.

The bitor operator is the text equivalent of |. There are two ways to access the bitor operator in your programs: include the header file iso646.h, or compile with the /Za (Disable language extensions) compiler option.

// expre_Bitwise_Inclusive_OR_Operator.cpp  
// compile with: /EHsc  
// Demonstrate bitwise inclusive OR  
#include <iostream>  
using namespace std;  
  
int main() {  
   unsigned short a = 0x5555;      // pattern 0101 ...  
   unsigned short b = 0xAAAA;      // pattern 1010 ...  
  
   cout  << hex << ( a | b ) << endl;   // prints "ffff" pattern 1111 ...  
}  

C++ Built-in Operators, Precedence and Associativity
C Bitwise Operators