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

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

uint16_t hex_to_uint(const char *str) {
    // Your logic here
    uint16_t result = 0;
    
    while (*str != '\0') {
        result = result * 16;
        
        char c = *str;
        
        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;
        }
        
        str++;
    }
    
    return result;
}

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

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