bca-mart.c

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

int money = 15;

int purchase(char *item, int cost) {
    int amount;
    printf("How many %s would you like to buy?\n", item);
    printf("> ");
    scanf("%d", &amount);

    if (amount > 0) {
        cost *= amount;
        printf("That'll cost $%d.\n", cost);
        if (cost <= money) {
            puts("Thanks for your purchse!");
            money -= cost;
        } else {
            puts("Sorry, but you don't have enough money.");
            puts("Sucks to be you I guess.");
            amount = 0;
        }
    } else {
        puts("I'm sorry, but we don't put up with pranksters.");
        puts("Please buy something or leave.");
    }

    return amount;
}

int main() {
    int input;

    setbuf(stdout, NULL);
    setbuf(stdin, NULL);
    setbuf(stderr, NULL);

    puts("Welcome to BCA MART!");
    puts("We have tons of snacks available for purchase.");
    puts("(Please ignore the fact we charge a markup on everything)");

    while (1) {
        puts("");
        puts("1) Hichew™: $2.00");
        puts("2) Lays® Potato Chips: $2.00");
        puts("3) Water in a Bottle: $1.00");
        puts("4) Not Water© in a Bottle: $2.00");
        puts("5) BCA© school merch: $20.00");
        puts("6) Flag: $100.00");
        puts("0) Leave");
        puts("");
        printf("You currently have $%d.\n", money);
        puts("What would you like to buy?");

        printf("> ");
        scanf("%d", &input);

        switch (input) {
            case 0:
                puts("Goodbye!");
                puts("Come back soon!");
                puts("Obviously, to spend more money :)");
                return 0;
            case 1:
                purchase("fruity pieces of goodness", 2);
                break;
            case 2:
                purchase("b̶a̶g̶s̶ ̶o̶f̶ ̶a̶i̶r̶ potato chips", 2);
                break;
            case 3:
                purchase("bottles of tap water", 1);
                break;
            case 4:
                purchase("generic carbonated beverages", 2);
                break;
            case 5:
                purchase("wonderfully-designed t-shirts", 20);
                break;
            case 6:
                if (purchase("super-cool ctf flags", 100) > 0) {
                    FILE *fp = fopen("flag.txt", "r");
                    char flag[100];

                    if (fp == NULL) {
                        puts("Hmm, I can't open our flag.txt file.");
                        puts("Sorry, but looks like we're all out of flags.");
                        puts("Out of luck, we just sold our last one a couple mintues ago.");
                        puts("[If you are seeing this on the remote server, please contact admin].");
                        exit(1);
                    }

                    fgets(flag, sizeof(flag), fp);
                    puts(flag);
                }
                break;
            default:
                puts("Sorry, please select a valid option.");
        }
    }
}