It's said that with polymorphism, we can access a derived class member field with it's base class object like this:
#include <iostream>
#include <string>
#include <vector>
using namespace std;
class Tool{
public:
Tool(){}
Tool(string name){
this->name = name;
}
virtual string getInfo(){
return name;
}
//protected:
string name;
};
class Computer: public Tool{
public:
Computer(string name, int price){
this->name = name;
this->price = price;
}
virtual string getInfo(){
return name + ": " + to_string(static_cast<long long>(price));
}
//protected:
int price;
};
class Person{
public:
Person(){}
Person(string name){
this->name = name;
}
virtual string getInfo(){
return name;
}
virtual void addTools(Computer cmp){
tools.push_back(cmp);
}
//protected:
vector<Tool> tools;
string name;
};
class Programmer: public Person{
public:
Programmer(string name, string job){
this->name = name;
this->job = job;
}
string getInfo(){
return name + ": " + job;
}
//protected:
string job;
};
int main(){
Person prs("Person");
Programmer prg("Daphloon", "programmer");
Person* prs1 = &prs;
Person* prs2 = &prg;
cout << prs1->getInfo() << endl; // result: Person
cout << prs2->getInfo() << endl; // result: Daphoon: programmer
Tool tl("Hammer");
Computer cmp("PC", 100);
Tool* tl1 = &tl;
Tool* tl2 = &cmp;
cout << tl1->getInfo() << endl; // result: Hammer
cout << tl2->getInfo() << endl; // result: PC: 100
prs2->addTools(cmp);
cout << prs2->tools[0].getInfo() << endl; // result: PC
// I expect the result will be: PC: 100
return 0;
}
The result wasn't what I expected. What I need is every derived class from Person
have a vector tools
that contains object that inherit from Tool
class. If it described with word, it will be, "This Person
, a Programmer
, has some tools
. His first Tool
is a Computer
. If you want to know what's it's price
, use getInfo()
."
- Why vector take the base class instead of the derived class?
- Is there any data loss from
cmp
object when i put it insidetools
vector? - Is this happen because
tools
vector member takeTool
as it's type?