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What does the vertical pipe ( | ) mean in C++?

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I have this C++ code in one of my programming books:

WNDCLASSEX wndClass = { 0 };
wndClass.cbSize = sizeof(WNDCLASSEX);
wndClass.style =  CS_HREDRAW | CS_VREDRAW;

What does the single pipe do in C++ windows programming?

like image 819
quakkels Avatar asked Apr 15 '12 16:04

quakkels


Video Answer


2 Answers

Bitwise OR operator. It will set all bits true that are true in either of both values provided.

For example CS_HREDRAW could be 1 and CS_VREDRAW could be 2. Then it's very simple to check if they are set by using the bitwise AND operator &:

#define CS_HREDRAW 1
#define CS_VREDRAW 2
#define CS_ANOTHERSTYLE 4

unsigned int style = CS_HREDRAW | CS_VREDRAW;
if(style & CS_HREDRAW){
    /* CS_HREDRAW set */
}

if(style & CS_VREDRAW){
    /* CS_VREDRAW set */
}

if(style & CS_ANOTHERSTYLE){
    /* CS_ANOTHERSTYLE set */
}

See also:

  • Wikipedia: Bitwise operation (Section OR)
  • Wikipedia: Mask (computing) Section( Common bitmask functions)
like image 62
Zeta Avatar answered Oct 12 '22 15:10

Zeta


| is called bitwise OR operator.

|| is called logical OR operator.

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Nawaz Avatar answered Oct 12 '22 15:10

Nawaz