Check if the String Numeric or Alphabetic

Code

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

void classify_string(const char *str) {
    
    uint8_t idx = 0;
    uint8_t label = 0;

    while(str[idx] != '\0') {
        if (((str[idx] >= 'A') && (str[idx] <= 'Z')) || ((str[idx] >= 'a') && (str[idx] <= 'z'))) {
            label |= (1 << 0);
        } else if (((str[idx] >= '0') && (str[idx] <= '9'))) {
            label |= (1 << 1);
        } else {
            label |= (1 << 2);
            break;
        }
        idx++;
    }

    if (label == 1) {
        printf("ALPHABETIC\n");
    }else if (label == 2) {
        printf("NUMERIC\n");
    }else if (label > 2) {
        printf("MIXED\n");
    }
}

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