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 result = 0;
    while(*str){
        result <<= 4;
        if(*str >= '0' && *str <='9'){
            result |= (*str-'0');
        }else if(*str >='A' && *str <='F'){
            result |= (*str - 'A' + 10);
        }else if(*str >= 'a' && *str <= 'f'){
            result |= (*str - 'a' + 10);
        }else{
            break;
        }
        str++;
    }
    return result;
}

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

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