Check if the String Numeric or Alphabetic

Code

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

void classify_string(const char *str) {
    uint8_t end = 0;
    uint8_t alpha = 0;
    uint8_t digit = 0;
    while (str[end] != '\0') {
        if (str[end] <= '9' && str[end] >= '0')
            digit++;
        else if ((str[end] >= 'A' && str[end] <= 'Z') || (str[end] >= 'a' && str[end] <= 'z'))
            alpha++;
        else {
            printf("MIXED");
            return;
        } 
            
        end++;
    }
    if (digit && !alpha)
        printf("NUMERIC");
    else if (!digit && alpha)
        printf("ALPHABETIC");
    else   
        printf("MIXED");
}

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