Многократное определение функции

Основной блок:

    #include <string>
    #include "golf.cpp"
    //extern void setgolf(golf& g, const char* name, int hc);
    //extern int setgolf(golf& g);
    //extern void handicap(golf& g, int hc);
    //extern void showgolf(const golf& g);
    int main()
    {
        golf andy;
        golf &lol=andy;
        using namespace std;
        cout << "Vvedite name: ";
        char *name =new char[Len];
        int ch;
        cin >> name;
        cout << "Vvedite handicap: ";
        cin >> ch;
        setgolf(lol,name,ch);
        return 0;
    }

Второй блок

    #include <iostream>
const int Len = 40;
struct golf {
    char fullname[Len];
    int handicap;
};

void setgolf(golf &g, const char* name,int hc) {
    std::cout << "*g.fullname=" << *g.fullname << std::endl << "g.handicap=" << g.handicap;
    *g.fullname = *name;
    g.handicap = hc;
    std::cout << "*g.fullname=" << *g.fullname << std::endl << "g.handicap=" << g.handicap;
}
int setgolf(golf& g) {
    std::cout << "Vvedite handicap: ";
    std::cin >> g.handicap;
    std::cout << "Vvedite ima: ";
    std::cin.get(g.fullname, Len);
    if (std::cin) return 1;
    else return(0);
}
void handicap(golf& g, int hc) {
    g.handicap = hc;
    std::cout << "Gandicap otnine =" << hc << std::endl;
}
void showgolf(const golf& g) {
    std::cout << "Name: " << g.fullname << "  handicap: " << g.handicap << std::endl;
}

https://docs.microsoft.com/ru-ru/cpp/error-messages/tool-errors/linker-tools-error-lnk2005?f1url=https%3A%2F%2Fmsdn.microsoft.com%2Fquery%2Fdev16.query%3FappId%3DDev16IDEF1%26l%3DRU-RU%26k%3Dk(LNK2005)%26rd%3Dtrue&view=vs-2019