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) {
    uint16_t result = 0;
    char c;
    while ((c = *str++) != '\0') {
        result <<= 4; 

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

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

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

Solving Approach