6.3/getch.c


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#include <stdio.h>
#include <stdlib.h>
#include <error.h>
#include <errno.h>
#include "getch.h"

#define MAXBUFF 100

int top;
char buff[MAXBUFF];

char getch(void)
{
	return (top > 0) ? buff[--top] : getchar();
}

void ungetch(char c)
{
	if (top < MAXBUFF)
		buff[top++] = c;
	else
	 	error(EXIT_FAILURE, ENOBUFS, "getch");
}