wait_yn.c

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

void main(void)
 {
   char letter;               // Letter typed by the user

   printf("Do you want to continue? (Y/N): ");

   letter = getch();                  // Get the letter
   letter = toupper(letter);          // Convert letter to uppercase
  
   while ((letter != 'Y') && (letter != 'N'))
     {
       putch(7);                        // Beep the speaker
       letter = getch();                // Get the letter
       letter = toupper(letter);         // Convert letter to uppercase
     }

   printf("/nYour response was %c/n", letter);
 }