計算沒有正確完成

Question

我對C++相當陌生，我被賦予了一個相當基本的程序，用戶可以用它來購買門票，但我在計算中遇到了一些問題。

這是我的代碼到目前爲止。

#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"; 

} 

，我遇到的問題是，當用戶從購買VVIP和/或VIP門票，爲TOTAL_PRICE計算沒有被這樣做的權利。但是，如果輸入價格3，則計算工作正常。

用戶購買vvip和/或vip =計算不正確。 用戶購買正常和vvip和/或vip =計算正確。

任何幫助將非常感激。這個代碼還沒有完成，但現在，這就是我所擁有的。

Answer 1

你似乎無法計算之前初始化priceN（其中N是1, 2, 3一個變量）：在只有一種類型的票的情況下

total_price = price1 + price2 + price3; 

，所以結果是不可預知的，因爲變量包含垃圾。

你應該這樣開始：

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