Check if the String Numeric or Alphabetic

Code

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

void classify_string(const char *str) {
    char *tmp = (char *)str;

    if (*tmp == '\0') {
        printf("MIXED");
    }

    uint8_t is_numeric = 0;
    uint8_t is_alphabetic = 0;
    uint8_t is_mixed = 0;

    while (*tmp != '\0' && !is_mixed && (!is_numeric || !is_alphabetic)) {
        if (*tmp >= '0' && *tmp <= '9') {
            is_numeric = 1;
        }
        else if ((*tmp >= 'a' && *tmp <= 'z') || (*tmp >= 'A' && *tmp <= 'Z')) {
            is_alphabetic = 1;
        }
        else {
            is_mixed = 1;
        }
        ++tmp;
    }

    if ((is_numeric && is_alphabetic) || is_mixed) {
        printf("MIXED");
        return;
    }

    if (is_numeric) {
        printf("NUMERIC");
    }

    if (is_alphabetic) {
        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