119. Convert Hexadecimal String to Integer Without strtol or sscanf functions

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

uint16_t hex_to_uint(const char *str) {
    // Your logic here
    uint16_t value = 0;
    char c = 0; 
    uint16_t digit = 0;
    for (size_t i = 0; str[i]; ++i) {
        c = str[i];
        if (c >= 'a' && c <= 'z') c = c & ~32;
        digit = (c >= 'A') ? (c - 'A' + 10) : (c - '0');
        value = (value << 4) | digit;
    }

    return value;
}

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

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