Convert Hexadecimal String to Integer Without strtol or sscanf functions

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

uint16_t hex_to_uint(const char *str) {
    int val = 0;
for (int i = 0; str[i]; i++) {
    char c = str[i];
    int digit = 0;
    if (c >= 'A' && c <='F') digit =  c - 'A' + 10;
    else if (c >= 'a' && c <='f') digit = c - 'a' + 10;
    else  digit = (c - '0');
    val = (val << 4) | digit;
}
    return val;
}

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

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