目前做家庭作业，我应该创建一个包含不同类型卡片的矢量。所以我创建了一个卡类和2个派生类（ID卡，银行卡）。每个班级都有自己独特的信息（姓名等）。我不知道如何在矢量中创建id和银行卡。另外，有人可以解释多态性以及如何在此代码中使用它？我试过用＆amp;但我不确定该符号的确切用法是什么。在此先感谢您的帮助。
std::cout << "Card Type: " ;
std::cin >> card_type;
while (card_type)
{
if (card_type == 1)
{
std::cout << "Institution name: ";
getline (std::cin, institute_name);
std::cin.ignore();
std::cout << "Cardholder name: ";
getline (std::cin, card_name);
std::cin.ignore();
std::cout << "Expiration date mmddyyyy (0 if none): ";
std::cin >> expire_date;
std::cout << std::endl <<std::endl;
Card* regular = new Card(institute_name, card_name, expire_date);
cardbook.push_back (regular);
}
else if (card_type == 2)
{
std::cout << "Institution name: ";
getline (std::cin, institute_name);
std::cin.ignore();
std::cout << "Cardholder name: ";
getline (std::cin, card_name);
std::cin.ignore();
std::cout << "Expiration date mmddyyyy (0 if none): ";
std::cin >> expire_date;
std::cout << "ID number: ";
std::cin >> identify_num;
std::cout << "DOB mmddyyyy (0 if not listed)";
std::cin >> birthdate;
std::cout << std::endl << std::endl;
IDCard* identification = new IDCard(institute_name, card_name, expire_date, identify_num, birthdate);
cardbook.push_back (identification);
}
else if (card_type == 3)
{
std::cout << "Institution name: ";
getline (std::cin, institute_name);
std::cin.ignore();
std::cout << "Cardholder name: ";
getline (std::cin, card_name);
std::cin.ignore();
std::cout << "Expiration date mmddyyyy (0 if none): ";
std::cin >> expire_date;
std::cout << "Account number: ";
std::cin >> account_num;
std::cout << "Card Security Code: ";
std::cin >> secure_code;
std::cout << std::endl << std::endl;
BankCard* bank = new BankCard (institute_name, card_name, expire_date, account_num, secure_code);
cardbook.push_back (bank);
}
答案 0 :(得分：0)
创建一个包含不同类型的向量
您可以通过创建类层次结构并在vector中存储指向基类型的指针来完成此操作。听起来你已经创建了层次结构，但是你没有显示你的代码，我无法进一步评论你的具体问题。
// This example creates a base type with 2 derived types and stores the
// derived types in a `vector` using a base type pointer.
//
// The polymorphism is observed when `Base::action` is called but
// `action` from the "real" type `Foo` and `Bar` is invoked.
#include <iostream>
#include <memory>
#include <vector>
class Base
{
public:
virtual ~Base() {}
virtual void action() const = 0;
};
class Foo : public Base
{
public:
void action() const override { std::cout << "Foo::action\n"; }
};
class Bar : public Base
{
public:
void action() const override { std::cout << "Bar::action\n"; }
};
int main()
{
// A `vector` of base type pointers
std::vector<std::unique_ptr<Base>> values;
// Add a `Foo` type to the `vector`
values.emplace_back(new Foo());
// Add a `Bar` type to the `vector`
values.emplace_back(new Bar());
// For each `v` (which is a `Base` pointer) in `values`
for(auto& v : values)
{
// Calling `action` through the `Base` pointer
v->action();
}
return 0;
}
Foo::action
Bar::action
如果您仍然遇到问题，请提出一个新问题，如果您希望获得有用的帮助，这也应该是一个更好的问题。请务必阅读以下内容：