Convert Hexadecimal String to Integer Without strtol or sscanf functions

Code

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

uint16_t hex_to_uint(const char *str) {
    // Your logic here
    uint16_t result = 0;
    while(((*str >= '0') && (*str <= '9')) ||
            ((*str >= 'A') && (*str <= 'F')) ||
            ((*str >= 'a') && (*str <= 'f')))
            {
                result = result<<4; // Make a room
                if((*str >= '0') && (*str <= '9'))
                {
                    result = result | ((*str - '0')&0x0F);
                }
                else if((*str >= 'A') && (*str <= 'F'))
                {
                    result = result | ((*str - 'A'+10)&0x0F);
                }
                else if((*str >= 'a') && (*str <= 'f'))
                {
                    result = result | ((*str - 'a'+10)&0x0F);
                }
                str++;
            }
    return result;
}

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

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

Solving Approach