Check if the String Numeric or Alphabetic

Code

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

void classify_string(const char *str) {
    // Your logic here
       int isNum = 1, isAlpha = 1;

    if (str[0] == '\0') { 
        printf("MIXED");
    }

    for (int i = 0; str[i] != '\0'; i++) {
        if (!(str[i] >= '0' && str[i] <= '9')) isNum = 0;
        if (!((str[i] >= 'A' && str[i] <= 'Z') || (str[i] >= 'a' && str[i] <= 'z'))) isAlpha = 0;
    }

    if (isNum) printf("NUMERIC");
    else if (isAlpha) 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