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;
    uint16_t value;

    for (int i = 0; str[i]; i++) {
        char c = str[i];

        if (c <= '9')
            value = c - '0';
        else if (c <= 'F')
            value = c - 'A' + 10;
        else
            value = c - 'a' + 10;

        result = result * 16 + value;
    }

    return result;
}

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

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