CODEWITHSUNDEEP
c++
Sarmad Ali
Sarmad Ali

Reputation: 122

Derived Class Insertion and extraction operator overloading and Casting between base to derived class

  1. Can I define separately stream insertion and extraction operators of base and derived classes?
  2. If we derive class from base class then how can I cast and overload stream insertion and extraction operator?

I have created a class VehicleType and bikeType and want to overload stream insertion and extraction operator for derived class because I need to read data from file because when I read data from file with variables of class so, I will lost more time. My question is that how I can cast derived class bikeType to vehicleType. 

#pragma once
#ifndef vehicleType_H
#define vehicleType_H
#include<string>
#include"recordType.h"
using namespace std;
class vehicleType
{
  private:
    int ID;
    string name;
    string model;
    double price;
    string color;
    float enginePower;
    int speed;
    recordType r1;
  public:
    friend ostream& operator<<(ostream&, const vehicleType&);
    friend istream& operator>>(istream&, vehicleType&);
    vehicleType();
    vehicleType(int id,string nm, string ml, double pr, string cl, float 
         enP, int spd);
    void setID(int id);
    int getID();
    void  recordVehicle();
    void setName(string);
    string getName();
    void setModel(string);
    string getModel();
    void setPrice(double);
    double getPrice();
    void setColor(string);
    string getColor();
    void setEnginePower(float);
    float getEnginePower();
    void setSpeed(int);
    int getSpeed();
    void print();
 };
  #endif
  #pragma once 
  #ifndef bikeType_H
  #define bikeType_H
  #include"vehicleType.h"
 #include<iostream>
 using namespace std;
 class bikeType :public vehicleType
   {
     private:
       int wheels;
     public:
        bikeType();
        bool  operator<=(int);
        bool operator>(bikeType&);
        bool operator==(int);
        bikeType(int wls, int id, string nm, string ml, double pr, string 
          cl,float enP, int spd);
        void setData(int id, string nm, string ml, double pr, string cl, 
        float enP, int spd);
        void setWheels(int wls);
        int getWheels();
        friend istream& operator>>(istream&, bikeType&);
        friend ostream& operator<<(ostream&, const bikeType&);
        void print();
         };
        #endif

I have defined all functions of base and derived classes but only stream insertion and stream extraction operators could not defined.

Upvotes: 1

Views: 567

Answers (2)

Volodymyr Lashko
Volodymyr Lashko

Reputation: 716

Add a virtual function to base class and define it in derived classes.

class vehicleType
{
    // ...
    virtual ostream& output(ostream& os) = 0;
};

class bikeType :public vehicleType
{
    // ...
    ostream& output(ostream& os) override
    {
        return os << "I am a bike!";
    }
};

Define output operator like this:

ostream& operator<<(ostream& os, const vehicleType& v)
{
    return v.ouput(os);
}

Upvotes: 1

eerorika
eerorika

Reputation: 238281

  1. Can I define separately stream insertion and extraction operators of base and derived classes?

Yes. As you have done.

  1. If we derive class from base class then how can I cast and overload stream insertion and extraction operator?

You can use a static cast to a reference to base if you would like to call the extraction operator of the base.

Upvotes: 0

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