我正在尝试创建Person对象的向量。但是我真的想存储从Person基类派生的Adult，Professor和Student对象。在询问this question后，我了解到我的问题是在对象拼接中，并且它会将派生类保存为Person类，因为这就是向量的含义。我试图修改代码以纠正这种情况，但我仍然遇到一些错误，需要一些额外的帮助。谢谢！
这是我的main.cpp代码：
#include "Person.h"
#include "Professor.h"
#include "Student.h"
#include "Adult.h"
#include <vector>
#include <string>
#include <iostream>
using namespace std;
template<typename T> void addPerson(vector<Person *> &personVector) {
cout << "DEBUG" << endl;
personVector.push_back(new T());
}
void addFriend(vector<Person *> &personVector) {
bool loop = true;
while (loop) {
cout << "\nWhich Person would you like to create? " << endl;
cout << " 1. Professor" << endl;
cout << " 2. Student" << endl;
cout << " 3. Adult" << endl;
int caseVar;
cin >> caseVar;
switch (caseVar) {
case 1:
addPerson<Professor>(personVector);
// old incorrect line: addPerson<Professor *>(personVector);
loop = false;
break;
case 2:
addPerson<Student>(personVector);
// old incorrect line: addPerson<Student *>(personVector);
loop = false;
break;
case 3:
addPerson<Adult>(personVector);
// old incorrect line: addPerson<Adult *>(personVector);
loop = false;
break;
default: cout << "Unknown Entry Please Try Again." << endl;
}
}
}
void displayFriends(vector<Person *> &personVector) {
if (personVector.size() > 1) {
for (unsigned i = 0; personVector.size() > i; i++)
cout << i+1 << ". " << personVector[i]->getName() << endl;
cout << "DEBUG" << endl;
}
}
void viewFriend(vector<Person *> &personVector) {
if (personVector.size() > 1) {
displayFriends(personVector);
cout << "Which # friend would you like to view? ";
int num;
cin >> num;
personVector[num-1]->coutPerson();
} else if (personVector.size() == 1) {
personVector[0]->coutPerson();
} else {
cout << "No friends to View." << endl;
}
}
void deleteElementFromArray(int element, vector<Person *> &personVector) {
vector<Person *> newPersonVector;
for (unsigned i = 0; personVector.size() > i; i++)
if (i != element - 1)
newPersonVector.push_back(personVector[i]);
personVector = newPersonVector;
}
void removeFriend(vector<Person *> &personVector) {
if (personVector.size() > 1) {
displayFriends(personVector);
cout << "Which # friend would you like to remove? ";
unsigned num;
cin >> num;
if (num <= personVector.size())
deleteElementFromArray(num, personVector);
else
cout << "Invalid Selection" << endl;
} else if (personVector.size() == 1) {
cout << "Removed one and only friend" << endl;
} else {
cout << "No friends to Remove." << endl;
}
}
int main() {
vector<Person *> personVector;
// Run Main Menu
cout << "Friends with Stuff" << endl;
cout << "Adding 5 friends to the list" << endl;
personVector.push_back(new Person("James"));
personVector.push_back(new Person("Martin"));
personVector.push_back(new Person("Sammi"));
personVector.push_back(new Person("Donny"));
personVector.push_back(new Person("Ronald"));
bool loop = true;
while (loop) {
cout << "\nWhat would you like to do? " << endl;
cout << " 1. Add New Friend" << endl;
cout << " 2. View Friend" << endl;
cout << " 3. Remove Friend" << endl;
cout << " 4. Clear Friends" << endl;
cout << " 5. Get Object" << endl;
cout << " 6. Exit" << endl;
int caseVar;
cin >> caseVar;
switch (caseVar) {
case 1:
addFriend(personVector);
break;
case 2:
viewFriend(personVector);
break;
case 3:
removeFriend(personVector);
break;
case 4:
personVector.clear();
break;
case 5:
break;
case 6:
loop = false;
break;
default: cout << "Unknown Entry Please Try Again." << endl;
}
}
}
我收到以下错误
InitializeBuildStatus:
1> Touching "Debug\FPVisualStudio.unsuccessfulbuild".
1>ClCompile:
1> main.cpp
1>\\cs1\cs_students\mlindahl15\cs172\final project\fpvisualstudio\main.cpp(12): error C2664: 'void std::vector<_Ty>::push_back(_Ty &&)' : cannot convert parameter 1 from 'Professor **' to 'Person *&&'
1> with
1> [
1> _Ty=Person *
1> ]
1> Reason: cannot convert from 'Professor **' to 'Person *'
1> Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
1> \\cs1\cs_students\mlindahl15\cs172\final project\fpvisualstudio\main.cpp(26) : see reference to function template instantiation 'void addPerson<Professor*>(std::vector<_Ty>)' being compiled
1> with
1> [
1> _Ty=Person *
1> ]
1>\\cs1\cs_students\mlindahl15\cs172\final project\fpvisualstudio\main.cpp(12): error C2664: 'void std::vector<_Ty>::push_back(_Ty &&)' : cannot convert parameter 1 from 'Student **' to 'Person *&&'
1> with
1> [
1> _Ty=Person *
1> ]
1> Reason: cannot convert from 'Student **' to 'Person *'
1> Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
1> \\cs1\cs_students\mlindahl15\cs172\final project\fpvisualstudio\main.cpp(30) : see reference to function template instantiation 'void addPerson<Student*>(std::vector<_Ty>)' being compiled
1> with
1> [
1> _Ty=Person *
1> ]
1>\\cs1\cs_students\mlindahl15\cs172\final project\fpvisualstudio\main.cpp(12): error C2664: 'void std::vector<_Ty>::push_back(_Ty &&)' : cannot convert parameter 1 from 'Adult **' to 'Person *&&'
1> with
1> [
1> _Ty=Person *
1> ]
1> Reason: cannot convert from 'Adult **' to 'Person *'
1> Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
1> \\cs1\cs_students\mlindahl15\cs172\final project\fpvisualstudio\main.cpp(34) : see reference to function template instantiation 'void addPerson<Adult*>(std::vector<_Ty>)' being compiled
1> with
1> [
1> _Ty=Person *
1> ]
1>
1>Build FAILED.
1>
1>Time Elapsed 00:00:02.90
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
我相信它告诉我，我的代码中有太多指针。但是我不明白为什么会这样。我有指针的唯一地方是说向量包含我需要在每种情况下重复的内容。这些指针是必需的，所以我没有对象切片。
Person.h
#ifndef PERSON_H
#define PERSON_H
#include <string>
#include "Date.h"
#include "PhoneNumber.h"
using namespace std;
class Person
{
protected:
string name;
Date birthday;
PhoneNumber phoneNumber;
string city, state;
public:
// Constructors
Person();
Person(string name) {
this->name = name;
birthday = Date();
phoneNumber = PhoneNumber("0000000000");
city = "Unknown";
state = "Unknown";
}
// Getter and Setter Methods
string getName();
void setName(string);
Date getBirthday();
// Methods
void coutPerson();
};
#endif
Person.cpp
#include "Person.h"
#include "PhoneNumber.h"
#include "Date.h"
#include <string>
#include <iostream>
using namespace std;
// Constructors
Person::Person() {
cin.ignore();
cout << "Name? ";
getline(cin, name);
cout << "Birthday: " << endl;
birthday.askUserForDate();
phoneNumber.create();
cout << "City? ";
getline(cin, city);
cout << "State? ";
getline(cin, state);
}
// Getter and Setter Methods
string Person::getName() {
return name;
}
void Person::setName(string name) {
this->name = name;
}
void Person::coutPerson() {
cout << name << endl;
birthday.coutDate();
phoneNumber.coutPhoneNumber();
cout << city << ", " << state << endl;
}
// Methods
Student.h
#ifndef STUDENT_H
#define STUDENT_H
#include "Person.h"
using namespace std;
class Student : public Person
{
private:
string dorm;
int dormRoom;
public:
// Constructors
Student();
Student(Student &);
// Getter and Setter Methods
// Methods
void coutPerson();
};
#endif
Student.cpp
#include "Student.h"
#include "Person.h"
#include <string>
#include <iostream>
using namespace std;
// Constructors
Student::Student() {
cin.ignore();
cout << "Dorm? ";
getline(cin, dorm);
cout << "Dorm Room #? ";
cin >> dormRoom;
}
// TODO Copy Constructors
// TODO Deconstructors
// Overload < > ==
Student::Student(Student &student) {
Person::Person(student);
dorm = student.dorm;
dormRoom = student.dormRoom;
}
void Student::coutPerson() {
cout << "DEBUG: Student::coutPerson()" << endl;
Person::coutPerson();
cout << "Dorm Room: " << this->dorm << " " << this->dormRoom << endl;
}
// Methods
答案 0 :(得分：2)
您需要删除模板参数中的*。
例如：
addPerson<Professor *>(personVector);
替换为：
addPerson<Professor>(personVector);
目前，您正在创建Professor **。
更新：在你的main()中，你应该使用new Person("Name")来创建人物，你现在正在使用的是没有意义的，即'采取这种类型的地址'正在运行，但这是一个非常糟糕的主意（获取在堆栈上创建的对象的地址）。
例如：
personVector.push_back(&Person("James"));
替换为：
personVector.push_back(new Person("James"));
更新2：请注意，您有责任在某个时候释放您正在分配的内存。
答案 1 :(得分：2)
您的模板参数是指针但不应该在您的方法中，例如template<typename T> void addPerson(...)您使用T创建了new的新实例，因此您创建了一个指向某个人的新指针（即new Person*()，这将导致Person***）
因此，只需将其称为：addPerson<Professor>(personVector);，它会将new T()转换为new Professor()，从而产生Professor*结果。
另一件事：
void deleteElementFromArray(int element, vector<Person *> personVector) {
vector<Person *> newPersonVector;
for (unsigned i = 0; personVector.size() > i; i++)
if (i != element - 1)
newPersonVector.push_back(personVector[i]);
personVector = newPersonVector;
}
首先，您要删除element - 1，因此请注意，您无法传递0（即element是一个基于一的索引）。
其次，您将newPersonVector分配给参数personVector。但是，由于您按值传递矢量（它被复制），因此该变量在该函数外部将不可见。
你有几个解决方案：
personVector删除项目，而不是复制那些不应删除的项目。使用personVector.erase(personVector.begin() + element)之类的东西（注意这里的语法可能不太正确，但你应该得到它）。void deleteElementFromArray(int element, vector<Person *>* personVector) personVector = removeFriend(personVector); 我个人更喜欢选项1，因为它重用了矢量，从而减少了复制操作。
答案 2 :(得分：1)
代码
addPerson<Professor *>(personVector);
尝试修改为：
addPerson<Professor>(personVector);