119. Convert Hexadecimal String to Integer Without strtol or sscanf functions

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

uint16_t hex_to_uint(const char *str) {
    uint16_t val = 0;
    while (*str != '\0'){
        int digit;
        if ( *str >= '0' && *str <= '9'){
            digit = *str - '0';
        }
        else if ((*str >= 'A' && *str <= 'F')){
            digit = *str - 'A' + 10;
        }
        else if ((*str >= 'a' && *str <= 'f')){
            digit = *str - 'a' + 10;
        }
        str++;
        val = (val << 4) | digit;
    }
    
    // Your logic here
    return val;
}

int main() {
    char hex[10];
    scanf("%s", hex);

    printf("%u", hex_to_uint(hex));
    return 0;
}