Check if the String Numeric or Alphabetic

Code

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

void classify_string(const char *str) {
    // Your logic here
    int i = 0;
    int alpha = 0;
    int num = 0;
    while (str[i] != '\0'){
        if ((str[i] >= 'A' && str[i] <= 'Z') || (str[i] >= 'a' && str[i] <= 'z')) ++alpha;
        else if (str[i] >= '0' && str[i] <= '9') ++num;
        // else printf("MIXED\n");
        ++i;
    }
    if (num == i) printf("NUMERIC\n");
    else if (alpha == i) printf("ALPHABETIC\n");
    else 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