关于操作符的重载，老是出错。。

#include <iostream>
using namespace std;
class money
{
    public:
        money(int _dollars, int _cents);
        void showmoney();
        int getdollars()
        {
            return dollars;
        }
        int getcents()
        {
            return cents;
        }
    private:
        int dollars;
        int cents;
};
money::money(int _dollars, int _cents)
{
    dollars = _dollars;
    cents =_cents;
}
void money::showmoney()
{
    cout << "Money:" << dollars << " . " << cents << endl;
}
money operator +(const money &a, const money &b)
{
    int _dollars = a.getdollars() + b.getdollars();
    int _cents = a.getcents() + b.getcents();
    return money(_dollars, _cents);
}
int main()
{
    money my(100, 25);
    money your(200, 50);
    money our = my + your;
    our.showmoney();
    return 0;
}