사과 팝니다 한 입 하세요~~

#include <stdio.h>

#include <stdlib.h>

​

typedef struct {

char* name;

int price;

int count;

} Item;

​

// Market inventory

Item items[] = {

{"Quiet Quiches", 10, 12},

{"Average Apple", 15, 8},

{"Fruitful Flag", 100, 1}

};

int numItems = sizeof(items) / sizeof(Item);

int coins = 40;

​

void displayItems() {

printf("\nWelcome to the market!\n=====================\n");

printf("You have %d coins\n", coins);

printf("\tItem\t\t\tPrice\tCount\n");

for (int i = 0; i < numItems; i++) {

printf("(%d) %s\t\t%d\t%d\n", i, items[i].name, items[i].price, items[i].count);

}

printf("(3) Sell an Item\n(4) Exit\n");

}

​

void buyItem() {

int choice, qty;

printf("Choose an option: ");

scanf("%d", &choice);

​

if (choice < 0 || choice >= numItems) {

if (choice == 4) exit(0);

printf("Invalid option!\n");

return;

}

​

printf("How many do you want to buy? ");

scanf("%d", &qty);

​

if (qty > items[choice].count) {

printf("Not enough inventory.\n");

} else {

int totalCost = items[choice].price * qty; // Vulnerable to underflow if qty is negative

if (totalCost > coins) {

printf("Not enough coins.\n");

} else {

items[choice].count -= qty;

coins -= totalCost; // Increases coins if qty is negative

printf("You bought %d %s(s).\n", qty, items[choice].name);

}

}

}

​

void sellItem() {

int choice, qty;

printf("Which item do you want to sell? ");

scanf("%d", &choice);

​

if (choice < 0 || choice >= numItems) {

printf("Invalid option!\n");

return;

}

​

printf("How many do you want to sell? ");

scanf("%d", &qty);

​

if (qty < 0 || qty > items[choice].count) {

printf("Invalid quantity.\n");

} else {

items[choice].count += qty;

coins += items[choice].price * qty;

printf("You sold %d %s(s).\n", qty, items[choice].name);

}

}

​

int main() {

int choice;

​

while (1) {

displayItems();

printf("Choose an option: ");

scanf("%d", &choice);

​

switch (choice) {

case 0:

case 1:

case 2:

buyItem();

break;

case 3:

sellItem();

break;

case 4:

printf("Exiting...\n");

return 0;

default:

printf("Invalid option!\n");

break;

}

}

return 0;

}