[C] Function keys

char * UserInput(int max) {
  BOOL EndInput = TRUE;
  unsigned int Count;
  int Count2 = 0, Count3 = 0, cursore = 0;
  char AllowedCh[] = {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', '\0'};
  char AllowedNum[] = {'1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '\0'};
  char *Buff;
  char Current = ' ';
  char provvisorio[2];
  char *definitivo;

  Buff = (char *) malloc((max + 1));
  definitivo = (char *) malloc((max + 1));
  Buff[0] = '\0';
  definitivo[0] = '\0';

  while(EndInput)
  {
      provvisorio[Count3] = getch();
      definitivo = strupr(provvisorio);
      definitivo[Count3 + 1] = '\0';
      Current = definitivo[Count3];
      switch(Current)
      {
         case 13: EndInput = FALSE;
                  Buff[Count2] = '\0';
                  break;

         case 8: Buff[Count2] = '\0';
                 if(cursore > 0)
                 {
                   printf("\b \b");
                   Count2--;
                   Buff[Count2] = '\0';
                   cursore--;
                 }
                 break;

         /*function keys exclusion*/
         case(0+65): break;
         case(0+66): break;
         case(0+67): break;
         case(0+68): break;
         case(0+69): break;
         case(0+70): break;
         case(0+71): break;
         case(0+72): break;
         case(0+73): break;
         case(0+74): break;
         /****************/

         default: if(max == 1)
                  {
                      for(Count = 0; Count < strlen(AllowedCh); Count++)
                      {
                         if(Current == AllowedCh[Count] && (Count2 < max))
                         {
                             printf("%c", Current);
                             Buff[Count2] = Current;
                             Count2++;
                             cursore++;
                          }
                      }
                      break;
                  }
                  else
                  {
                      for(Count = 0; Count < strlen(AllowedNum); Count++)
                      {
                         if(Current == AllowedNum[Count] && (Count2 < max))
                         {
                             printf("%c", Current);
                             Buff[Count2] = Current;
                             Count2++;
                             cursore++;
                         }
                      }
                      break;
                  }
      }
  }
  return Buff;
} //End UserInput

Code (markup):

I have a problem with this code, if I press F7, F8, F9, F10, pagup, home introduce valid character for input.
Well have you some suggestion about how to recognize if a function key or a char key is pressed and accept only the chars?
How to do in my code?

Example, if I press F7 it will input A. I don't want this!

 

Hmm.. If i remember correctly, when getch() is used, function keys send two codes instead of one. First a 0 is returned from getch() (which is an indication this is an extended key), and then a special code is returned (which causes the A to be printed).

So, all you need to do is make a check that if getch() returns a zero, then call it again to get the actual code of the key.