1lineprint

#include <iostream>
#include <string>

class mystring :public std::string
{
    public:
    mystring(): std::string()
        {}
    mystring(const char* str): std::string(str)
        {}
    mystring operator *(int n)
    {
        mystring ret;
        for (int i = 0; i < n; ++i) {
            ret.append(data());
        }
        return ret;
    }
    mystring operator =(char* s)
    {
        return mystring(s);
    }
    void print_n_times(int n)
    {
        std::cout<< *this * 3;
    }
};

int main()
{
    mystring("Hello world \n").print_n_times(3);
}