Check if the String Numeric or Alphabetic

Code

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

void classify_string(const char *str) {
    int a=0,n=0;
    for(int i=0;str[i]!=0;i++){
        if(str[i]>='0'&&str[i]<='9') n++;
        else if((str[i]>='A'&&str[i]<='Z')||(str[i]>='a'&&str[i]<='z')) a++;
        else{
            printf("MIXED\n");
            return;
        }
    }
    if(a>0&&n==0) printf("ALPHABETIC\n");
    else if(n>0&&a==0) printf("NUMERIC\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