Set or Clear a Specific Bit in a Register

Code

#include <stdio.h>

unsigned char modifyBit(unsigned char reg, int pos, int mode) {
    // Write your code here
    // 10 = 00001010
    if(mode==1)
        return reg|=(1<<pos);
    else if(mode==0)
        return reg&=~(1<<pos);
}

int main() {
    unsigned char reg;
    int pos, mode;
    scanf("%hhu %d %d", &reg, &pos, &mode);
    printf("%d", modifyBit(reg, pos, mode));
    return 0;
}

Solving Approach

• Bitwise Operations Used
  • Set bit: reg | (1 << pos)
    • Shifts 1 to the left by pos places and ORs it with reg.
    • This ensures the bit at pos becomes 1.
  • Clear bit: reg & ~(1 << pos)
    • Shifts 1 to the left by pos places, inverts it with ~, and ANDs with reg.
    • This ensures the bit at pos becomes 0.
• Steps
  • Take input values: reg, pos, and mode.
  • If mode = 1, set the bit at position pos.
  • If mode = 0, clear the bit at position pos.
  • Return the modified value.