strcmp

int strcmp(const char *str1, const char *str2)

int main ()
{
   char str1[15];
   char str2[15];
   int ret;


   strcpy(str1, "abcdef");
   strcpy(str2, "ABCDEF");

   ret = strcmp(str1, str2);

   if(ret < 0)
   {
      printf("str1 is less than str2");
   }
   else if(ret > 0) 
   {
      printf("str2 is less than str1");
   }
   else 
   {
      printf("str1 is equal to str2");
   }
   
   return(0);
}

#include 
#include 

int main ()
{
  char key[] = "apple";
  char buffer[80];
  do {
     printf ("Guess my favorite fruit? ");
     fflush (stdout);
     scanf ("%79s",buffer);
  } while (strcmp (key,buffer) != 0);
  puts ("Correct answer!");
  return 0;
}