Getränkeding

automat.c

#include <stdio.h>
#include <stdlib.h>

#define LEN(arr) ((int) (sizeof(arr) / sizeof(arr)[0]))
#define PREIS_TO_INT(arr, adr, row) ((int) strtol(arr[row][1], adr, 10))
#define NAME 0
#define PREIS 1

static const char *getraenk[][2] = {
	{ "Cola", "120" },
	{ "Fanta", "130" },
	{ "Sprite", "150" },
	{ "H20", "140" }
};

static const int muenze[] = {
	1,
	2,
	5,
	10,
	20,
	50,
	100,
	200,
	500
};

static const int selection(void);
static const void print_menu(void);
static const int find_price(int);
static const void deal(int);
static const int pay(void);
static const void payback(int);
static const void deliver(int);

int selection(void)
{
	int auswahl;

	while (1) {
		printf("Select: ");
		scanf("%d", &auswahl);
		if (auswahl == 0) {
			puts("Bye-bye!");
			exit(0);
		} else if (auswahl - 1 < 0 || auswahl - 1 >= LEN(getraenk)) {
			puts("Such an idiot ...");
		} else {
			printf("You've chosen %s.\n", getraenk[auswahl - 1][NAME]);
			break;
		}
	}

	return auswahl - 1;
}

void print_menu(void)
{
	int i;
	char *c = NULL;

	puts("Thirsty?");
	puts("--------");

	for (i = 0; i < LEN(getraenk); i++)
		printf("%2d %10.10s %3d\n",
				(i + 1),
				getraenk[i][NAME],
				PREIS_TO_INT(getraenk, &c, i));

	printf("%2d %10.10s\n", 0, "Exit");
}

int find_price(int gewaehlt)
{
	char *c = NULL;
	int p = PREIS_TO_INT(getraenk, &c, gewaehlt);

	printf("%s costs %d.\n", getraenk[gewaehlt][NAME], p);

	return p;
}

void deal(int preis)
{
	do {
		printf("Still to give: %d\n", preis);
		preis -= pay();
	} while (preis > 0);

	if (preis < 0)
		payback(preis * -1);
}

int pay(void)
{
	int einwurf;

	while (1) {
		printf("Input: ");
		scanf("%d", &einwurf);
		for (int i = 0; i < LEN(muenze); i++) {
			if (einwurf == muenze[i]) {
				printf("You've put in %d.\n", einwurf);
				return einwurf;
			}
		}
		puts("What kind of coin is it? It's wrong. Really.");
	}
}

void payback(int preis)
{
	printf("Your change: %d\n", preis);
	puts("Please collect:");
	for (int i = LEN(muenze) - 1; i >=0; i--) {
		printf("\t%2d x %3d\n", preis / muenze[i], muenze[i]);
		preis %= muenze[i];
	}
}

void deliver(int gewaehlt)
{
	printf("Take your drink: %s.\n\n", getraenk[gewaehlt][NAME]);
}

int main(void)
{
	int gewaehlt;

	while (1) {
		print_menu();
		gewaehlt = selection();
		deal(find_price(gewaehlt));
		deliver(gewaehlt);
	}
}

// vim: set ft=c :