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#include <iostream>
#include <iomanip>
#include <map>
#include <cstdlib>
#include <cstdint>
#include <cstring>
#include <limits>
#include <stdexcept>

class String {
private:
    char *data;
    size_t len;
public:
    String() : len(0) {data = new char[1];}
    String(const char *str) {
        len = strlen(str) + 1;
        data = new char [len];
        strcpy(data, str);
    }

    friend std::ostream& operator<< (std::ostream& out, const String str) {
        out << str.data;
        return out;
    }

    virtual ~String() {
        delete[] data;
    }
};

std::map<unsigned long, String> strings;

void test()
{
    std::cout << strings[0];
}

int main (int argc, const char *argv[])
{
    strings[0] = "test";
    test();
    std::cout << strings[0];
}