Check if the String Numeric or Alphabetic

Code

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

void classify_string(const char *str) {
    // Your logic here
    int num = 0;
    int alpha = 0;
    while(*str != '\0'){
        if(*str >= '0' && *str <= '9'){
            num = 1;
        }
        else if(*str >= 'A' && *str <= 'Z' || *str >= 'a' && *str <= 'z'){
            alpha = 1;
        }
        else {
            printf("MIXED");
            return;
        }
        str++;
    }
    
    if(num && !alpha)printf("NUMERIC");
    else if(!num && alpha)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