Check if the String Numeric or Alphabetic

Code

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

void classify_string(const char *str) {
    int i;
    int digits;
    int letters;
    int others;
    char c;

    i = 0;
    digits = 0;
    letters = 0;
    others = 0;
    while(str[i])
    {
        c = str[i];
        if((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z'))
            letters++;
        else if(c >= '0' && c <= '9')
            digits++;
        else
            others++;

        i++;
    }


    if(digits == i)
    {
        printf("NUMERIC");
    }
    else if(letters == i)
        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