C++ - Bitwise OR operator
The Bitwise OR operator (|) is a binary operator which takes two bit patterns of equal length and performs the logical OR operation on each pair of corresponding bits. It returns 1 if either or both bits at the same position are 1, else returns 0.
Bit_1 | Bit_2 | Bit_1 | Bit_2 |
---|---|---|
0 | 0 | 0 |
1 | 0 | 1 |
0 | 1 | 1 |
1 | 1 | 1 |
The example below describes how bitwise OR operator works:
50 | 25 returns 59 50 -> 110010 (In Binary) | 25 -> | 011001 (In Binary) ---- -------- 59 <- 111011 (In Binary)
The code of using Bitwise OR operator (|) is given below:
#include <iostream> using namespace std; int main (){ int x = 50; int y = 25; int z; //Bitwise OR operation z = x | y; //Displaying the result cout<<"z = "<<z; return 0; }
The output of the above code will be:
z = 59
Example: Find largest power of 2 less than or equal to given number
Consider an integer 1000. In the bit-wise format, it can be written as 1111101000. However, all bits are not written here. A complete representation will be 32 bit representation as given below:
00000000000000000000001111101000
Performing
00000000000000000000001111111111
Adding one to this result and then right shifting the result by one place will give largest power of 2 less than or equal to 1000.
00000000000000000000001000000000
The below code will calculate the largest power of 2 less than or equal to given number.
#include <iostream> using namespace std; static int MaxPowerOfTwo(int N) { //changing all right side bits to 1. N = N | (N>>1); N = N | (N>>2); N = N | (N>>4); N = N | (N>>8); N = N | (N>>16); //adding 1 to N makes smallest power //of 2 greater than given number N = N + 1; //right shift by one position makes //largest power of 2 less than or //equal to given number N = N >> 1; return N; } int main() { cout<<"MaxPowerOfTwo(100) = "<< MaxPowerOfTwo(100)<<"\n"; cout<<"MaxPowerOfTwo(500) = "<< MaxPowerOfTwo(500)<<"\n"; cout<<"MaxPowerOfTwo(1000) = "<< MaxPowerOfTwo(1000)<<"\n"; return 0; }
The above code will give the following output:
MaxPowerOfTwo(100) = 64 MaxPowerOfTwo(500) = 256 MaxPowerOfTwo(1000) = 512
❮ C++ - Operators