03. Products and Cities C++ Exam

#include <iostream>
#include <string>
#include <map>

int main()
{
    using namespace std;

    size_t n;
    cin >> n;

    map<string, double> data;
    for (;data.size() < n;) //while(data.size() < n)
    {
        string city;
        double price, quantity;
        cin >> city >> price >> quantity;
        data[city] += price * quantity;
    }

    for (const auto& c : data)
        cout << c.first << ' ' << c.second << endl;

    return 0;
}