#include<stdio.h>
#include<ctype.h>

int is_digit_string(const char *s){
    for(int i = 0; s[i]!= '\0'; i++){
        if(!isdigit(s[i])){
            return 0;
        }
    }
    return 1;
}
int main(){
    char str1[] ="12345";
    char str2[] ="T;
    if(is_digit_string(str1)){
        printf("The string \"%s\" contains only digits.\n", str1);
    }else{
        printf("The string \"%s\" contains non_digit characters.\n", str1);
    }
    
        printf("The string \"%s\" contains only digits.\n", str2);
   
       
    
    return 0;
}