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

#include <stdio.h>
#include <stdint.h>
uint8_t hex_to_val(char c)
{
    if (c >= '0' && c <= '9') return c - '0';
    else if (c >= 'A' && c <= 'F') return c - 'A' + 10;
    else if (c >= 'a' && c <= 'f') return c - 'a' + 10;
    else return 0;
}
uint16_t hex_to_uint(const char *str) {
    // Your logic here
    uint16_t res=0;
    for(int i=0;str[i];i++)
    {
        res <<=4;
        res |= hex_to_val(str[i]);
    }
    return res;
}

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

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