Operator Overloading Problem(->, <, >)

[Peterwkc]

Hello all expert C++ programmer, i fairly new to C++ programming.

I have a class cellphone which contain dynamic pointer.

I have create (example)ten cellphone.

I want to ask user for the input and store in the list and finally sort the list according to the brand of cellphone.

I learn C++ by myself. Therefore, i hope someone can guide me in this matter. I not asking for solution but guideline.

Why i need overload ->, << , < or >> in order to manipulate my class ?

Below is my program :

Header File :

// Header File 
 
 
/* Don't define user copy constructor and 
   assignment operator if the class has
   embedded object such as std::string
*/
 
#pragma once
 
#include <iostream>
#include <string>
#include<list>
 
using std::ostream;
using std::string;
using std::list;
 
class cellphone
{
    int phone_number;
    string service;
    string brand;
public:
    cellphone() : phone_number(0), 
        service(), brand(){}
    // User Define Constructor
 
    cellphone(const cellphone &nokia)
        :phone_number(nokia.phone_number), 
        service(nokia.service),
        brand(nokia.brand){}
    // Copy Constructor
 
    cellphone& operator=(const cellphone &nokia)
    {
        if (this != &nokia)
        this->phone_number = nokia.phone_number;
        this->service = nokia.service;
        this->brand = nokia.brand;
        return *this;
    }
    // Assignment Operator
 
    friend ostream& operator<<(ostream& output, const cellphone &nokia)
    {
        output << nokia.phone_number 
            << nokia.service << nokia.brand;
        return output;
    }
    // User Defined Insertion Operator
 
    void setPhone_Number();
    void setService();
    void setBrand();
    void dispaly(list<cellphone> &);
 
    ~cellphone(){}
};
 
int setNum_Phone();
 

Exception Header File :

// Exception Header File
#pragma once
 
#include<string>
 
using std::string;
 
class invalid
{
    string description;
public:
    invalid() : description(){}
    invalid(string error) : description(error){}
 
    string getDescription()const{return description;}
    ~invalid(){}
};
 
 

Implementation File :

#include<iostream>
#include<list>
#include<exception>
#include "List-1.h"
#include "Invalid.h"
 
using namespace std;
 
int main(int argc, char *argv[])
{
    int loop, result;
    try
    {
        result = setNum_Phone();    
    }
    catch(const invalid &error)
    {
        cerr << error.getDescription();
    }
 
    cellphone *lg = new cellphone [result];
 
 
    for (loop=0;loop<result;loop++)
    {
        try
        {
            lg[loop]->setPhone_Number();
        }
        catch(invalid &any)
        {
            cerr << any.getDescription();
        }
 
        lg[loop]->setService();
        lg[loop]->setBrand();
    }
 
    list<cellphone> nokia;
    nokia.push_back(lg);
 
    lg.dispaly(nokia);
 
//    nokia.sort();
/*
    cellphone samsung(lg);
    cellphone motorola;
    motorola = lg;  
    cout << motorola << "\n" << samsung;
*/    
    delete [] lg;
    return 0;
}
 
int setNum_Phone()
{
    int number;
    cout << "How many Cellphone : ";
    cin >> number;
    invalid error("Number of cellphone cannot zero");
    if (number == 0)throw error;
 
    system("cls");
    return number;
}
 
void cellphone::setPhone_Number()
{
    cout << "Enter Phone Number : ";
    cin >> phone_number;
    while(cin.get() !='\n');
    if (phone_number <0)
    {
        invalid error("Phone Number cannot zero");
        throw error;
    }
}
 
void cellphone::setService()
{
    cout << "Enter Service : ";
    getline(cin, service);
}
 
void cellphone::setBrand()
{
    cout << "Enter Brand of Cellphone :";
    getline(cin, brand);
}
 
void cellphone::dispaly(std::list<cellphone> &nokia)
{
    list<cellphone>::const_iterator citera;
 
    for (citera=nokia.begin();citera!=nokia.end();citera++)
    {
        cout << "\n\n\n" << *citera;
    }
}
 
 

What is embedded object ?

I want to know more except string.

I guess it something like vector or list.
Thanks for your help.

Your help is greatly appreciated by me and others.

[Peterwkc]

I have typed wrong information. My class doesn't have any pointer.

[Peterwkc]

I am a C++ programmer from C.

Thanks.

[weaknessforcats]

The short answer is that you do not need to overload operators to manipulate your class.

For example, to display an object of your class you could:

cellphone thephone;
thephone.display();
 

by writing a display method. However, if you want you display your class by:
[code=cpp]

cellphone thephone;
cout << thephone << endl;
 

then you will need to overload the << operator.

If you want to sort a bunch of cellphone objects and you use the STL sort, the sort will need to compare two cellphones. It will call the operator<. To use the sort, you would need an operator<.

I would start by not overloading any operators. Then add the overloads as I need them.