Check if the String Numeric or Alphabetic

Code

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

void classify_string(const char *str) {
    // Your logic here
    int digit=0,alpha=0,mixed=0;
    int index=0;
    while(str[index]!='\0'){
        if((str[index]>='A' && str[index]<='Z') || (str[index]>='a' && str[index]<='z'))
        {
            alpha++;
        }
        else if(str[index]>='0' && str[index]<='9'){
            digit++;
        }
        else mixed++;
        index++;
    }
    // printf("DIGIT=%d \nALPHA=%d \nMIXED=%d\n",digit,alpha,mixed);
    index;
    if(digit==index) printf("NUMERIC");
    else if(alpha==index) 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