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 val=0;
    uint8_t digit =0;
    for(int i=0; str[i] != '\0'; i++)
    {
        if(str[i] >='0' && str[i] <= '9')
        digit = str[i]-'0' ;
        else if( str[i] >='A' && str[i] <= 'F' ) 
        digit = str[i] - 'A' + 10 ;
        else if( str[i] >='a' && str[i] <= 'f' ) 
        digit = str[i] - 'a' + 10 ;
        
        //printf("%X", digit);
        val = (val<<4)| digit;
        digit=0;
        
    }
    return val;
}

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

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