18. Set Multiple Bits in 8-bit Register

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

uint8_t set_range(uint8_t reg, uint8_t start, uint8_t end) {
    // Your code here
    int maskStart = 0, maskEnd = 0;
    for(int i=0; i<=end; i++){
        maskEnd = maskEnd << 1;
        maskEnd += 1;
    }
    for(int i=0; i<start; i++){
        maskStart = maskStart << 1;
        maskStart += 1;
    }
    maskEnd ^= maskStart;
    reg = reg | maskEnd;
    return reg ;
}

int main() {
    uint8_t reg, start, end;
    scanf("%hhu %hhu %hhu", &reg, &start, &end);
    printf("%u", set_range(reg, start, end));
    return 0;
}