How do you set only certain bits of a byte in C without affecting the rest?

Question

Say I have a byte like this 1010XXXX where the X values could be anything. I want to set the lower four bits to a specific pattern, say 1100, while leaving the upper four bi

Answer 1

Use bitwise operator or | when you want to change the bit of a byte from 0 to 1.

Use bitwise operator and & when you want to change the bit of a byte from 1 to 0

Example

#include 

int byte;
int chb;

int main() {
// Change bit 2 of byte from 0 to 1
byte = 0b10101010;    
chb = 0b00000100;       //0 to 1 changer byte
printf("%d\n",byte);    // display current status of byte

byte = byte | chb;      // perform 0 to 1 single bit changing operation
printf("%d\n",byte);

// Change bit 2 of byte back from 1 to 0
chb = 0b11111011;       //1 to 0 changer byte

byte = byte & chb;      // perform 1 to 0 single bit changing operation
printf("%d\n",byte);
}

Maybe there are better ways, I dont know. This will help you for now.