Nạp chồng toán tử gán trong C++

#include <iostream>
using namespace std;

class KhoangCach
{
private:
    int met;
    int centimet;
public:
    // phan khai bao cac constructor can thiet
    KhoangCach() {
        met = 0;
        centimet = 0;
    }
    KhoangCach(int m, int c) {
        met = m;
        centimet = c;
    }
    void operator=(const KhoangCach& K)
    {
        met = K.met;
        centimet = K.centimet;
    }
    // phuong thuc de hien thi khoang cach
    void hienthiKC()
    {
        cout << "\nDo dai bang m la: " << met << 
            "\nVa do dai bang cm la: " << centimet << endl;
    }

};
int main()
{
    KhoangCach K1(10, 16), K2(15, 50);
    cout << "Khoang cach dau tien: ";
    K1.hienthiKC();
    cout << "\n-------------------\n";
    cout << "Khoang cach thu hai:";
    K2.hienthiKC();
    // su dung toan tu gan
    K1 = K2;
    cout << "\n-------------------\n";
    cout << "Khoang cach dau tien: ";
    K1.hienthiKC();   return 0;
}