May the 4th be with you! It’s Jedi day, or Star Wars day, or whatever. Here’s a binary puzzle for you, one which demonstrates how the bitwise OR operator can be used to set bits in an integer value.

#include <stdio.h>

char *binbin(int n);

int main()
{
    int input,result,bit,x;

    bit = 1;
    printf("Type a number between 0 and 255: ");
    scanf("%d",&input);
    printf("%s\n========\n",binbin(input));
    for(x=0;x<8;x++)
    {
        result = bit | input;
        printf("%s\n",binbin(result));
        bit*=2;
    }
    return(0);
}

char *binbin(int n)
{
    static char bin[9];
    int x;

    for(x=0;x<8;x++)
    {
        bin[x] = n & 0x80 ? '1' : '0';
        n <<= 1;
    }
    bin[x] = '\0';
    return(bin);
}

The code asks for input, a teensy int value (8 bits). That value is then manipulated using the logical OR for each bit position, 0 through 7.

Here's how the output looks when zero is input:

Type a number between 0 and 255: 0
00000000
========
00000001
00000010
00000100
00001000
00010000
00100000
01000000
10000000

You can see the single bit cascading across each value. That bit is set sequentially no matter which value you input. The bit is always set by the bitwise |, which is why I call that operator the set-bit operator.