Convert Hexadecimal String to Integer Without strtol or sscanf functions

Code

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

uint16_t hex_to_uint(const char *str) {
    unsigned int result=0;
    int i=0;
    while(str[i] != '\0'){
        char currentchar = str[i];
        if(currentchar >= 'a' && currentchar <= 'f'){
            currentchar -= 'a' - 'A';
        }
        if((currentchar >= '0' &&  currentchar <= '9') || (currentchar >= 'A' &&  currentchar <= 'F')){
            uint16_t hexvalue= (currentchar >= '0' && currentchar <= '9') ? (currentchar - '0') : (currentchar - 'A'+10);
            result = result * 16 + hexvalue;
        }
        i++;
    }
    return result;
}

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

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

Solving Approach