getch.c

Get a character from the stdin, put it into a buffer (which has a size of BUFSIZE).

getch gets a character out of the buffer (if stdin is finished, an EOF is returned).

fgetch replaces stdin by a file.

ungetch puts back a character into the buffer.

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

char buf[BUFSIZE];
int sp = 0;

int getch(void) {
    return (sp > 0) ? buf[--sp] : getchar();
}

int fgetch(FILE *fp) {
    return (sp > 0) ? buf[--sp] : getc(fp);
}

void ungetch(int c) {
    if (sp >= BUFSIZE)
	fprintf(stderr, "ERROR.  ungetch: buffer is full.\n");
    else
	buf[sp++] = c;
}

Back to the home page of Wei-Chang Shann.
Connect to the home page of Department of Mathematics, National Central University, Taiwan.

shann@math.ncu.edu.tw