Check if the String Numeric or Alphabetic

Code

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

void classify_string(const char *str) {
    // Your logic here
    bool digits = false; 
    bool letters = false;
    bool symbols = false;

    // take care of empty string edge case
    if (*str == '\0'){
        printf("MIXED"); 
        return;
    }

    while(*str != '\0'){
        if ((*str >= '0') && (*str <= '9')){
            digits = true;
        }
        // [a-z] or [A-Z]
        else if (((*str >= 'a') && (*str <= 'z'))
                 || ((*str >= 'A') && (*str <= 'Z'))){
            letters = true;
        }
        else {
            symbols = true;
        }
        str++;       
    }

    if ((symbols && (digits || letters))){
        printf("MIXED");
    }
    else if (digits && letters){
        printf("MIXED");
    }
    else if (digits){
        printf("NUMERIC");
    }
    else if (letters){
        printf("ALPHABETIC");
    }
}

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