为什么我的 CPP 代码不起作用？它不输出任何东西

Question

这是一款买卖来自其他国家的货物并尝试赚钱的游戏。这是一项正在进行的工作。当我运行它时，没有输出，它只是说按任意键关闭程序。

#include <iostream>
#include <string>
#include <stdlib.h>
using namespace std;

void options();

bool shipmentFull = false;
int money;

class gun {
public:
    gun(string NAME, int VALUE) {
        name = NAME, value = VALUE;
    }
private:
    string name;
    int value;
    friend class shipment;
};

gun AK47("AK47", 250);
gun Glock17("Glock 17", 475);
gun RPG7("RPG 7", 500);
gun Mossberg590("Mossberg 590", 600);
gun Barrett("Barrett 82A1", 3000);
gun arsenal[5] = { AK47, Glock17, RPG7, Mossberg590, Barrett };

class shipment {
public:
    shipment(gun G, int QUANTITY, int PRICE) : g(G) {
        quantity = QUANTITY, price = PRICE, total = price * quantity;
    }
private:
    gun g;
    int quantity;
    int price;
    int total;
    friend void buy();
    friend void sell();
};

class country {
public:
    country(string NAME) : name(NAME) {}
    string name;
    int buyPrice = 0;
    int sellPrice = 0;
    friend void buy();
    friend void sell();
};

country china("China");
country america("America");
country russia("Russia");
country mexico("Mexico");
country afghanistan("Afghanistan");
country world[5] = { china, america, russia, mexico, afghanistan };

void buy() {
    if (!shipmentFull) {
        // WIP
    }
    else {
        std::cout << "You already have a shipment, you need to sell it before you can buy another!" << endl;
        system("pause");
        system("CLS");
        options();
    }
}

void sell() {
    if (shipmentFull) {
        // WIP
    }
    else {
        std::cout << "You do not have a shipment. If you want to sell a shipment, you need to buy one first!" << endl;
        system("pause");
        system("CLS");
        options();
    }
}

int startMoney() {
    int x;
    std::cout << "How much money would you like to start with?" << endl << "Min: 5000" << endl << "Max: 20000" << endl;
    std::cin >> x;
    if (money <= 20000 && x >= 5000) {
        system("CLS");
        return x;
    }
    else {
        system("CLS");
        std::cout << "Invalid number, please try again!" << endl;
        system("pause");
        system("CLS");
        startMoney();
    }
}

void options() {
    std::cout << "1: Buy a shipment" << endl << "2: Sell a shipment" << endl;
    int option;
    std::cin >> option;
    switch (option) {
    case 1:
        system("CLS");
        buy();
    case 2:
        system("CLS");
        sell();
    default:
        system("CLS");
        std::cout << "Error, invalid input." << endl;
        system("pause");
        system("CLS");
        options();
    }
}

int main() {
    int start = 0;
    return 0;
    if (start == 0) {
        money = startMoney();
        start += 1;
    }
    options();
    system("CLS");
    main();
}

我期待它首先检查游戏是否已经开始，如果还没有运行 startMoney 函数，并获得用户想要开始的金额。然后，它应该运行 options 功能，询问它是否要购买或出售货物。它需要一个数字作为输入，并且根据输入它应该运行销售或购买功能，然后返回到 main 并循环回来，因为这些功能还没有做任何事情。

Answer 1

在：

int main() {
  int start = 0;
  return 0;

删除语句：

return 0;