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 result = 0;
    for (int i = 0; str[i] != '\0'; i++) {
        result <<= 4;
        if (str[i] >= '0' && str[i] <= '9') result |= str[i] - '0';
        else if (str[i] >= 'A' && str[i] <= 'F') result |= str[i] - 'A' + 10;
        else if (str[i] >= 'a' && str[i] <= 'f') result |= str[i] - 'a' + 10;
    }  
    return result;  
}

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

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