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

/* get the next operator or operand */
int getop(char s[])
{
  int i, c;

  while ((s[0] = c = getc(stdin)) == ' ' || c == '\t')
      /* no-op */ ;

  s[1] = '\0';
  if ( !isdigit(c) && c != '.')
    return c;    /* not a number */

  i = 0;
  if ( isdigit(c) )   /* collect the integer part */
    while (isdigit(s[++i] = c = getc(stdin)))
      ;

  if (c == '.')       /* collect the fraction part */
    while (isdigit(s[++i] = c = getc(stdin)))
      ;

  s[i] = '\0';
  if (c != EOF)
    ungetc(c, stdin);
  return '0';
}