/* "由函數所構成的陣列" (function dispatch table) 範例. */

#include <stdio.h>
#include <string.h>
#include "sitio.h"

int row=1, col=1;

void move_left(void)
{
    --col;
    if (col <= 0) col += 70;
}

void move_down(void)
{
    ++row;
    if (row > 20) row -= 20;
}

void move_up(void)
{
    --row;
    if (row <= 0) row += 20;
}

void move_right(void)
{
    ++col;
    if (col > 70) col -= 70;
}

int main(void)
{
    int ch;
    char * p;
    char const valid_keys[] = "hjkl";
    void (* dispatch[])(void) = {
	move_left, move_down, move_up, move_right
    };

    beginsitio();
    clearscr();
    gotorc(23, 1);
    printf("use hjkl to move the cursor, any other key to quit");

    do {
	gotorc(row, col);
	ch = getkey();
	if (ch == EOF) break;
	p = strchr(valid_keys, ch);
	if (p) (*dispatch[p - valid_keys])();
    } while (p);

    clearscr();
    gotorc(24, 1);
    endsitio();
    return 0;
}