#include <stdio.h>
#include "calc.h"

#define BUFSIZE 100

char buf[BUFSIZE]; /* buffer for ungetch */
int bufp = 0;      /* next free position in buf */

int getch() /* get a (possibly pushed back) character */
{
	return (bufp > 0) ? buf[--bufp] : getchar();
}

void ungetch(int c) /* push character back on input */
{
	if (bufp >= BUFSIZE)
		fprintf(stderr, "ungetch: too many characters\n");
	else
		buf[bufp++] = c;
}