CODEWITHSUNDEEP
c++classstlmultiset
Dev Krishna Sadana
Dev Krishna Sadana

Reputation: 77

C++: How to create a multiset of objects of a class?

Here is my class declaration:

class Person
{
private:
    string name;

public:
    void showData()
    {
        cout << name << endl;
    }
    void insertData()
    {
        cin >> name;
    }
    bool operator<(Person p)
    {
        return name < p.name;
    }
};

Now I am trying to create a multiset of objects of person class, How to do so? Here is the main function which I to wrote:

int main()
{
    multiset<Person> m;
    for (int i = 0; i < 6; i++)
    {
        Person p;
        p.insertData();
        m.insert(p);
    }
    multiset<Person>::iterator it;
    // for (it = m.begin(); it != m.end(); it++)
    // {
    //    cout << it.name << endl;
    // }
}

Upvotes: 0

Views: 213

Answers (1)

john
john

Reputation: 87959

You need to define your operator< in a slightly different way. I would define it as a friend not a class member, but if it is a class member it should be const.

So this is OK

class Person
{
    ...
    bool operator<(Person p) const
    {
        return name < p.name;
    }
};

but I would do it like this

class Person
{
    ...
    friend bool operator<(const Person& x, const Person& y)
    {
        return x.name < y.name;
    }
};

Upvotes: 2

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