#include <stdbool.h>// check string to verify it consists// of only lower-case alpha charactersbool is_lowercase(const char *string) { char *p = string; do { if ((*p < 'a' || *p > 'z') && *p != '\0') { // INSERT MISSING CODE } } while (*p++ != '\0'); return true;}

It seems like you want to complete the function is_lowercase which checks if a string consists only of lower-case alpha characters. The missing code should return false if a non-lowercase character is found. Here is the completed function:

#include <stdbool.h>

bool is_lowercase(const char *string) {
  char *p = string;
  do {
    if ((*p < 'a' || *p > 'z') && *p != '\0') {
      return false;
    }
  } while (*p++ != '\0');
  
  return true;
}

In this function, we iterate over each character in the string. If we find a character that is not a lowercase letter (i.e., it is either less than 'a' or greater than 'z'), we immediately return false. If we reach the end of the string without finding any non-lowercase characters, we return true.