"No viable overloaded" = "why"?

Question

I am doing a project for one of my classes, and I am sure that I have almost finished the project. Basically, I have to enter tickets for 2 people, and I need to find the maximum and minimum price. I need to overload the * and / operators to fix this problem for the project. In addition, an announcement friendis a necessity for this project using teacher instructions.

Now, for the problem. I am trying to save the correct ticket variable (either t1 or t2) in t3 so that I can return this to the main one. When I use "=" to set t1-t3, it says "no viable overloaded" = "". Below is my code:

#include <iostream>

using namespace std;

class ticket
{
public:
    ticket();
    double input();
    double output();
    friend ticket operator *(const ticket &t1, const ticket &t2);
    friend ticket operator /(const ticket &t1, const ticket &t2);
private:
    void cost();
    string name;
    double miles, price;
    int transfers;
};


int main()
{
    ticket customer1, customer2, customer3;

    //------------------------------------------------
    cout << "*** Customer 1 ***" << endl;
    customer1.input();
    cout << "--- Entered, thank you ---" << endl;


    cout << "*** Customer 2 ***" << endl;
    customer2.input();
    cout << "--- Enter, thank you ---" << endl;
    //------------------------------------------------



    //------------------------------------------------
    cout << "Testing of the * operator: " << endl;
    customer3 = customer1 * customer2;
    cout << "*** Database printout: ***" << endl;
    customer3.output();
    cout << endl;
    cout << "--- End of Database ---" << endl;
    //------------------------------------------------


    //------------------------------------------------
    cout << "Testing of the / operator:" << endl;
    customer3 = customer1 / customer2;
    cout << "*** Database printout: ***" << endl;
    customer3.output();
    cout << endl;
    cout << "--- End of Database ---" << endl;
    //------------------------------------------------


        return 0;
}

ticket operator *(const ticket &t1, const ticket &t2)
{
    ticket t3;

    if (t1.price > t2.price)
        t3 = t1.price;
    else
        t3 = t2.price;
    return t3;
}
ticket operator /(const ticket &t1, const ticket &t2)
{
    ticket t3;

    if (t1.price < t2.price)
        t3 = t1.price;
    else
        t3 = t2.price;
        return t3;
}
ticket::ticket()
{
}

double ticket::input()
{
    cout << "Miles? ";
    cin >> miles;

    cout << endl << "Transers? ";
    cin >> transfers;

    cout << endl << "Name? ";
    cin >> name;

    cost();

    cout << endl << "Price is: " << price << endl;

    return miles;
}

double ticket::output()
{
    cout << name << '\t' << miles << "mi \t " << transfers << " transfers \t" << price;
    return miles;
}

void ticket::cost()
{
    price = (.5 * miles) - (50 * transfers);
}

Answer 1

operator= ticket, double. ticket.

Answer 2

, .

getter const, . . :

class CPath {
private: 
    std::string m_extension; 
public: 
    std::string GetExtension() const {
        if (m_extension.length()==0) {
            m_extension = "txt";
        }
        return m_extension; 
    }
}

const, m_extension mutable.

Answer 3

-

set_price(const& double price)

, ,

 if (t1.price > t2.price)
        t3.set_price(t1.price);
    else
        t3.set_price(t2.price);