Bit Operations using Macros

#include <stdio.h>
#include <stdint.h>

uint8_t modify_register(uint8_t reg)
{
    int arr[4] = {2, 7, 3, 5};
    int *ptr = arr;

    reg |=  (1U << *ptr);       // bit 2
    reg |=  (1U << *(++ptr));   // bit 7
    reg &= ~(1U << *(++ptr));   // clear bit 3
    reg ^=  (1U << *(++ptr));   // toggle bit 5

    return reg;
}

int main(void)
{
    uint8_t reg;
    scanf("%hhu", &reg);
    printf("%u", modify_register(reg));
    return 0;
}