Check if the String Numeric or Alphabetic

Code

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

void classify_string(const char *str) {
    bool has_alpha = false;
    bool has_digit = false;
    while(*str != '\0') {
        if((*str >= 'A' && *str <= 'Z') || (*str >= 'a' && *str <= 'z') ){
           has_alpha = true;
        } else if((*str >= '0') && (*str <= '9')){
            has_digit = true;
        } else {
            printf("MIXED");
            return;
        }
        str++;
    }
    if (has_alpha && has_digit) {
        printf("MIXED\n");
    } else if (has_alpha) {
        printf("ALPHABETIC\n");
    } else if (has_digit) {
        printf("NUMERIC\n");
    } else {
        printf("MIXED\n"); // empty or weird case
    }
}

int main() {
    char str[101];
    fgets(str, sizeof(str), stdin);

    // Remove newline
    uint8_t i = 0;
    while (str[i]) {
        if (str[i] == '\n') {
            str[i] = '\0';
            break;
        }
        i++;
    }

    classify_string(str);
    return 0;
}

Solving Approach