/** note, I have included a main at the bottom of this code for testing
purposes.  Only put the prototype at the top of your main and put the
function after main.
**/

/*********************************************************************
*  This function is designed to input an integer value from the user *
*  and guarantee that it is greater than or equal to some low value. *
*  It also will check to make sure that a character has not been     *
*  entered.  If it has, the subprogram will clean out the rest of the*
*  input stream.  Try it and see how it works.                       *
*  It also checks for 327a or 23.398 and says they are errors also.  *
*********************************************************************/

/** the scanf() returns and integer value indicating the number of
  correct conversions it was able to make.  I use the return value to
  see if the value was converted to integer correctly.

    the while((iochar = getchar()...  loop is complete in the one
  statement.  It removes all left over stuff in the input stream 

  the isspace() function is in ctype.h  so include this library 
**/

 
void get_int(int *value, int low)
{
  int iochar, error_flag;

  do
  {
    error_flag = scanf(" %d", value);
    if (error_flag != 1)
    {
      printf("\nEnter an integer value please ");
      *value = low - 1;
      while((iochar = getchar()) != '\n');
    }
    else
    {
      iochar = getchar();
      if (!isspace(iochar))
      {
        printf("\nInvalid integer input, try again \n");
        while((iochar = getchar()) != '\n');
        *value = low - 1;
      } 
      else if (*value < low)
        printf("\nEnter an integer >= to %d ", low);
    }
  }
  while ((error_flag != 1) || (*value < low));
}


void main(void)
{
   int x;

   get_int(&x, 0);
   printf("\ndone x = %d\n", x); 
}