bookstore

#include <iostream>
#include <vector>
#include <algorithm>
#include <iomanip>
#include <cstdlib>
#include <sstream>

using namespace std;

class CSales {
public:
    CSales () {}
    CSales (string i, int p, int c) {
        this->m_isbn = i;
        this->m_price = p;
        this->m_count = c;
        this->m_revenue = p*c;
    }
    friend ostream & operator << ( ostream &os, const CSales &x ); //const;
    friend istream & operator >> ( istream &is, const CSales &x );

    string m_isbn;
    int m_price;
    int m_count;
    int m_revenue;

};
ostream & operator << ( ostream &os, const CSales &x ) {
    os << "isbn: " << x.m_isbn << endl;
    os << "price: " << x.m_price << endl;
    os << "sold: " << x.m_count << "x." << endl;
    os << "____________" << endl;

    return os;
}
istream & operator >> ( istream &is, const CSales &x ) {
    if ( is >> x.m_isbn >> x.m_price >> x.m_count ) {
        x.m_revenue = x.m_count*x.m_price;
    }

    return is;
}

bool cmp_isbn(const CSales *a, const CSales *b) {
    return (a->m_isbn < b->m_isbn);
}

int main() {
    vector<CSales*> dbs1;
    CSales *candidate = new CSales();

    cout << "start entering transactions (isbn, price, quantity):" << endl;

    while ( cin >> *candidate ) {
        //sorted by isbn
        auto iter = lower_bound(dbs1.begin(), dbs1.end(), candidate, cmp_isbn);
        //found book in database
        if ( iter != dbs1.end() && (*iter)->m_isbn == candidate->m_isbn ) {
            (*iter)->m_count += candidate->m_count;
            (*iter)->m_revenue += candidate->m_count * candidate->m_price;
        } else {
            //add book to database
            dbs1.insert(iter, candidate);
        }
    }

    for (auto it : dbs1) {
        cout << it;
    }

    return 0;
}