C++ 在不调用构造函数的情况下创建向量元素
假设我有两个等级:汽车和服务。是否可以为汽车和服务类的两个矢量对象(注:我不知道是否实际被视为矢量对象)创建元素。一旦创建了这两个元素,我只希望稍后调用car类构造函数来调用服务构造函数以获取用户信息 还有,如果可能的话,不必将服务构造函数更改为方法也可以吗C++ 在不调用构造函数的情况下创建向量元素,c++,class,object,vector,elements,C++,Class,Object,Vector,Elements,假设我有两个等级:汽车和服务。是否可以为汽车和服务类的两个矢量对象(注:我不知道是否实际被视为矢量对象)创建元素。一旦创建了这两个元素,我只希望稍后调用car类构造函数来调用服务构造函数以获取用户信息 还有,如果可能的话,不必将服务构造函数更改为方法也可以吗 using namespace std; // I know this is not the best, prof wants us to use it class Car { Car() { //Get data from
using namespace std; // I know this is not the best, prof wants us to use it
class Car { Car() { //Get data from user } };
class Service { Service(){ //Get data from user } };
int main () {
int num;
vector<Car> car;
vector<Service> service;
car.push_back(Car{});
service.push_back();
for (int i = 0; i < car.size(); i++)
car[i].display(i);
cout << endl << car.size() + 1 << ". exit";
cin >> num;
service[num].Service::Service();
}
使用命名空间std;//我知道这不是最好的,教授希望我们使用它
类Car{Car(){//从用户}获取数据};
类服务{Service(){//从用户}获取数据};
int main(){
int-num;
矢量车;
向量服务;
车。向后推(车{});
服务。推回();
对于(int i=0;i cout从C++11开始,就有了向量和其他容器的列表初始化
这意味着,可以在初始化时将元素枚举放入向量中
您可以在其中使用自己的类构造函数:
std::vector<Car> cars {Car(...), Car(...), Car(...)}; //C++11
std::vector cars{Car(…),Car(…),Car(…)};//C++11
因为我还不能评论你的问题,这是你所期望的吗?自从C++11以来,你就有了vector和其他容器的列表初始化
这意味着,可以在初始化时将元素枚举放入向量中
您可以在其中使用自己的类构造函数:
std::vector<Car> cars {Car(...), Car(...), Car(...)}; //C++11
std::vector cars{Car(…),Car(…),Car(…)};//C++11
既然我还不能评论你的问题,这是你所期望的吗?我建议使用std::map
,而不是std::vector
,这是你任务中自然而然的选择。通过使用它,你将只存储有效的服务元素
map<int,Service> service;
car.push_back(Car{});
for (int i = 0; i < car.size(); i++)
car[i].display(i);
cout << endl << car.size() + 1 << ". exit";
cin >> num;
service[num]; //Service constructor will be called
地图服务;
车。向后推(车{});
对于(int i=0;i cout我建议使用std::map
而不是从任务中自然选择的std::vector
。通过使用它,您将只存储有效的服务元素
map<int,Service> service;
car.push_back(Car{});
for (int i = 0; i < car.size(); i++)
car[i].display(i);
cout << endl << car.size() + 1 << ". exit";
cin >> num;
service[num]; //Service constructor will be called
地图服务;
车。向后推(车{});
对于(int i=0;i cout我想你在找这样的东西:
class Car {
private:
std::string _make;
std::string _model;
std::string _vinNumber;
std::size_t _year;
public:
Car() : _year( 0 ) {} // default
Car( const std::string& make, const std::string& model,
const std::string& vinNumber, const std::size_t& year ) :
_make( make ), _model( model ),
_vinNumber( vinNumber ), _year( year ) {
}
void setCarInfo( const std::string& make, const std::string& model,
const std::string& vinNumber, const std::size_t& year ) {
_make = make;
_model = model;
_vinNumber = vinNumber;
_year = year;
}
std::string makeOf() const { return _make; }
std::string modelOf() const { return _model; }
std::string vinNumberOf() const { return _vinNumber; }
std::size_t yearOf() const { return _year; }
};
class Service {
private:
std::string _dealership;
std::size_t _currentMiles;
public:
Serivce() {}
std::string dealershipOf() const { return _dealership; }
std:size_t currentMilesOf() const { return _currentMiles; }
void setOrChangeDealership( const std::string& dealership ) {
_dealership = dealership;
}
void setOrChangeCurrentMiles( std::size_t miles ) {
_currentMiles = miles;
}
void setOrChangeCurrentMiles( const std::size_t& miles ) {
_currentMiles = miles;
}
};
int main() {
std::vector<Car> cars;
std::vector<Service> services;
// you can add Car to vector by either default constructor
// to be filled out later or by user defined constructor
cars.push_back( Car( "Honda", "Civic", "75273250323XMD252AG9", 2017 ) );
// or
cars.push_back( Car() );
// then you can at some point in time update elements in container
cars[i].setCarInfo( "Dodge", "Charger", "9259356M325D2680A217B", 2015 );
// As with the service class there is only a "default" constructor
services.push_back( Service() );
// Service's members will have to be updated manually and later.
return 0;
}
A a();
编译器将在A
上调用A()
的A;
行在幕后,因此它实际上看起来像这样:
class Car {
private:
std::string _make;
std::string _model;
std::string _vinNumber;
std::size_t _year;
public:
Car() : _year( 0 ) {} // default
Car( const std::string& make, const std::string& model,
const std::string& vinNumber, const std::size_t& year ) :
_make( make ), _model( model ),
_vinNumber( vinNumber ), _year( year ) {
}
void setCarInfo( const std::string& make, const std::string& model,
const std::string& vinNumber, const std::size_t& year ) {
_make = make;
_model = model;
_vinNumber = vinNumber;
_year = year;
}
std::string makeOf() const { return _make; }
std::string modelOf() const { return _model; }
std::string vinNumberOf() const { return _vinNumber; }
std::size_t yearOf() const { return _year; }
};
class Service {
private:
std::string _dealership;
std::size_t _currentMiles;
public:
Serivce() {}
std::string dealershipOf() const { return _dealership; }
std:size_t currentMilesOf() const { return _currentMiles; }
void setOrChangeDealership( const std::string& dealership ) {
_dealership = dealership;
}
void setOrChangeCurrentMiles( std::size_t miles ) {
_currentMiles = miles;
}
void setOrChangeCurrentMiles( const std::size_t& miles ) {
_currentMiles = miles;
}
};
int main() {
std::vector<Car> cars;
std::vector<Service> services;
// you can add Car to vector by either default constructor
// to be filled out later or by user defined constructor
cars.push_back( Car( "Honda", "Civic", "75273250323XMD252AG9", 2017 ) );
// or
cars.push_back( Car() );
// then you can at some point in time update elements in container
cars[i].setCarInfo( "Dodge", "Charger", "9259356M325D2680A217B", 2015 );
// As with the service class there is only a "default" constructor
services.push_back( Service() );
// Service's members will have to be updated manually and later.
return 0;
}
A a();
使用它的默认构造函数。我想您正在寻找这样的东西:
class Car {
private:
std::string _make;
std::string _model;
std::string _vinNumber;
std::size_t _year;
public:
Car() : _year( 0 ) {} // default
Car( const std::string& make, const std::string& model,
const std::string& vinNumber, const std::size_t& year ) :
_make( make ), _model( model ),
_vinNumber( vinNumber ), _year( year ) {
}
void setCarInfo( const std::string& make, const std::string& model,
const std::string& vinNumber, const std::size_t& year ) {
_make = make;
_model = model;
_vinNumber = vinNumber;
_year = year;
}
std::string makeOf() const { return _make; }
std::string modelOf() const { return _model; }
std::string vinNumberOf() const { return _vinNumber; }
std::size_t yearOf() const { return _year; }
};
class Service {
private:
std::string _dealership;
std::size_t _currentMiles;
public:
Serivce() {}
std::string dealershipOf() const { return _dealership; }
std:size_t currentMilesOf() const { return _currentMiles; }
void setOrChangeDealership( const std::string& dealership ) {
_dealership = dealership;
}
void setOrChangeCurrentMiles( std::size_t miles ) {
_currentMiles = miles;
}
void setOrChangeCurrentMiles( const std::size_t& miles ) {
_currentMiles = miles;
}
};
int main() {
std::vector<Car> cars;
std::vector<Service> services;
// you can add Car to vector by either default constructor
// to be filled out later or by user defined constructor
cars.push_back( Car( "Honda", "Civic", "75273250323XMD252AG9", 2017 ) );
// or
cars.push_back( Car() );
// then you can at some point in time update elements in container
cars[i].setCarInfo( "Dodge", "Charger", "9259356M325D2680A217B", 2015 );
// As with the service class there is only a "default" constructor
services.push_back( Service() );
// Service's members will have to be updated manually and later.
return 0;
}
A a();
编译器将在A
上调用A()
的A;
行在幕后,因此它实际上看起来像这样:
class Car {
private:
std::string _make;
std::string _model;
std::string _vinNumber;
std::size_t _year;
public:
Car() : _year( 0 ) {} // default
Car( const std::string& make, const std::string& model,
const std::string& vinNumber, const std::size_t& year ) :
_make( make ), _model( model ),
_vinNumber( vinNumber ), _year( year ) {
}
void setCarInfo( const std::string& make, const std::string& model,
const std::string& vinNumber, const std::size_t& year ) {
_make = make;
_model = model;
_vinNumber = vinNumber;
_year = year;
}
std::string makeOf() const { return _make; }
std::string modelOf() const { return _model; }
std::string vinNumberOf() const { return _vinNumber; }
std::size_t yearOf() const { return _year; }
};
class Service {
private:
std::string _dealership;
std::size_t _currentMiles;
public:
Serivce() {}
std::string dealershipOf() const { return _dealership; }
std:size_t currentMilesOf() const { return _currentMiles; }
void setOrChangeDealership( const std::string& dealership ) {
_dealership = dealership;
}
void setOrChangeCurrentMiles( std::size_t miles ) {
_currentMiles = miles;
}
void setOrChangeCurrentMiles( const std::size_t& miles ) {
_currentMiles = miles;
}
};
int main() {
std::vector<Car> cars;
std::vector<Service> services;
// you can add Car to vector by either default constructor
// to be filled out later or by user defined constructor
cars.push_back( Car( "Honda", "Civic", "75273250323XMD252AG9", 2017 ) );
// or
cars.push_back( Car() );
// then you can at some point in time update elements in container
cars[i].setCarInfo( "Dodge", "Charger", "9259356M325D2680A217B", 2015 );
// As with the service class there is only a "default" constructor
services.push_back( Service() );
// Service's members will have to be updated manually and later.
return 0;
}
A a();
使用其默认构造函数。您是否正在寻找std:vector
?请参阅。请描述您试图更好地解决的问题(问题描述,最小化,而不是您试图在代码中执行的操作)在对象的构造中,不必从用户那里获取输入,而是编写一个函数,它要求您所需要的,然后将其传递给对象的构造函数。然后,您可以返回该对象并使用它将其分配给您想要的向量元素。您应该开始阅读C++的初学者书籍。什么是继承,什么是OOP?第二次调用一个构造函数“有时会晚些”,这绝对是C++工作的错误想法。所以你应该从基本的开始,直到构造函数运行之前你不能有一个对象。为什么不把默认的构造函数中的<代码> //数据从用户< /代码>移到函数<代码> Car GETCARFRONMIN()中。
和服务getServiceFromInput()
?您是否正在寻找标准:向量
?请参阅。请描述您试图更好地解决的问题(问题描述,最小化,而不是您试图在代码中执行的操作)在对象的构造中,不必从用户那里获取输入,而是编写一个函数,它要求您所需要的,然后将其传递给对象的构造函数。然后,您可以返回该对象并使用它将其分配给您想要的向量元素。您应该开始阅读C++的初学者书籍。什么是继承,什么是OOP?第二次调用一个构造函数“有时会晚些”,这绝对是C++工作的错误想法。所以你应该从基本的开始,直到构造函数运行之前你不能有一个对象。为什么不把默认的构造函数中的<代码> //数据从用户< /代码>移到函数<代码> Car GETCARFRONMIN()中。
和服务getServiceFromInput()
?我想为我的两个类都创建对象,这两个类都有构造函数。我希望两个对象都添加元素,尽管我只希望调用汽车类构造函数,而不希望调用服务类构造函数。我想为我的两个类都创建对象,这两个类都有构造函数我希望两个对象都添加元素,尽管我只希望调用car类构造函数,而不希望调用服务类构造函数。