c++ - 计算不正确

Question

我是 c++ 的新手，我被指派去做一个相当基本的程序，用户可以用它来买票，但我在计算方面遇到了一些问题。

到目前为止，这是我的代码。

#include <iostream>

using namespace std;

int main()
{
double type_ticket, num_tickets, price1, price2, price3, total_price, decision;

cout << "Welcome to the ticket kiosk.";
cout << "\n";
cout << "\n";
cout << "1. VVIP - RM 200";
cout << "\n";
cout << "2. VIP - RM 150";
cout << "\n";
cout << "3. Normal - RM 100" << endl;
cout << "\n";


do
{
cout << "Please select the category of ticket you would like to purchase: ";
cin  >> type_ticket;
cout << "\n";


if (type_ticket == 1)
{
cout << "How many would you like: ";
cin  >> num_tickets;
cout << "\n";
price1 = num_tickets * 200;
cout << "The price is: RM " << price1 << endl;
cout << "\n";
cout << "\n";
cout << "1. YES" << endl;
cout << "2. NO" << endl;
cout << "\n";
cout << "Would you like to continue purchasing more tickets: ";
cin  >> decision;
cout << "\n";
}


else if (type_ticket == 2)
{
cout << "How many would you like: ";
cin  >> num_tickets;
cout << "\n";
price2 = num_tickets * 150;
cout << "The price is: RM " << price2 << endl;
cout << "\n";
cout << "\n";
cout << "1. YES" << endl;
cout << "2. NO" << endl;
cout << "\n";
cout << "Would you like to continue purchasing more tickets: ";
cin  >> decision;
cout << "\n";
}


else if (type_ticket == 3)
{
cout << "How many would you like: ";
cin  >> num_tickets;
cout << "\n";
price3 = num_tickets * 100;
cout << "The price is: RM " << price3 << endl;
cout << "\n";
cout << "\n";
cout << "1. YES" << endl;
cout << "2. NO" << endl;
cout << "\n";
cout << "Would you like to continue purchasing more tickets: ";
cin  >> decision;
cout << "\n";
}


else
{
cout << "You have entered an invalid input, please try again. " << endl;
cout << "\n";
}


}
while (decision == 1);

total_price = price1 + price2 + price3;
cout << "The grand total is: RM " << total_price << endl;
cout << "\n";
cout << "Thank you for using this service today, we hope you enjoy the show." << endl;
cout << "\n";

}

我遇到的问题是当用户从 vvip 和/或 vip 购买门票时，total_price 的计算不正确。但是，当输入价格 3 时，计算工作正常。

用户购买 vvip 和/或 vip = 计算不正确。用户购买正常和 vvip 和/或 vip = 计算正确。

非常感谢任何帮助。

仅供引用，此代码尚未完成，但就目前而言，这就是我所拥有的。

Answer 1

您似乎没有在计算之前初始化 priceN(其中 N 是 1, 2, 3 之一)变量:

total_price = price1 + price2 + price3;

在只有一种类型的票的情况下，结果是不可预测的，因为变量包含垃圾。

你应该开始:

double price1 = 0;
double price2 = 0;
double price3 = 0;